A Fertility God is a Stock God role whose job is to create, cultivate or nurture new life, or to help create conditions in which life can thrive.
They often overlap with a Love God and Food God, though not always. "Fertility" means a lot of things to different people and cultures, and thus it's not that uncommon for a god with a wider role to have "fertility" as only one of its spheres. A god wholly devoted to it is usually some type of Odd Job God except for a Proud Merchant Race, a society of Explosive Breeders, or an agrarian society, where they are often a Patron God or sometimes even promoted to Top God. Even a Proud Warrior Race understands that it's important not to piss off the god responsible for feeding its armies.
By default, almost every Earth Mother or Mother Nature spirit doubles as a fertility goddess, but Nature Is Not Nice. A Nature Spirit may spend millions of years cultivating an entire species, only to wipe them all out with a single natural disaster. A pure Fertility God will usually only advocate for the creation and reproduction of life; they may even be opposed to a God/Entity of Death or Destroyer Deity, and works will often contrast the two. If they succeed in upsetting the balance, the world may eventually face an Overpopulation Crisis or some other Green Aesop in which life itself overtakes the Earth like a cancer.
They may also double as a Hot God and Sex God, if hanky-panky is within their definition of "fertility". They may also be responsible for a Mystical Pregnancy or two, often helping a mother (or "father") become pregnant after a single intimate act, or sometimes even no intimacy at all, often with tons and tons of offspring. They may also be the person having a bunch of kids themselves, sometimes by many different partners.
Their worshippers are usually Nature Lovers or exhibit Purity Personified, and the gods themselves usually lean toward Light in a work that utilizes Light/Darkness Juxtaposition, with an alignment that can range anywhere from Lawful Good to True Neutral. Evil versions, however, do exist, and may be a Monster Progenitor or Mother of a Thousand Young.
- Marvel Universe:
- The Norse goddess Freya, kin to Thor, was originally portrayed as a goddess of fertility. Not much else was known about her. Later stories, however, claimed that "Freya" (or "Freyja") was simply another name used by the Queen of Asgard (and Thor's step-mother) Frigga. It's also claimed that it's an alias which was also used by the Asgardian goddess of sex, beauty and seduction, Amora the Enchantress.
- The Incredible Hercules is considered a god of male fertility; this basically shows itself in his voracious sexual appetite and sex appeal. While the Marvel continuity is rather vague on the amount of children he's had over the millennia, he's considered the possible ancestor of numerous superheroes and supervillains.
- Gaea the Earth Mother is revealed to be the same Earth Goddess from every pantheon, such as "Jord" from Norse myth and "Haumea" from Hawaiian myth. Naturally, as a "Mother" goddess, she is also depicted as solving a large number of problems by giving birth to the solution, such as giving birth to Typhon in an attempt to kill the Olympian Gods, giving birth to the Demogorge to kill the Elder Gods, and giving birth to Thor (before retcons) to kill Giants and other monsters. While acting as one of the co-rulers of Asgard, she was even depicted holding an unidentified newborn in her arms.
- Poison Ivy has commonly been worshipped as a nature and fertility goddess, due to her sexually-appealing appearance and ability to grow entire forests even in urbanized areas and other places where plant life should not be sustainable. As a scientist (and misanthrope), Ivy is usually quick to to dismiss these claims, but will also take advantage of believers to fulfill whatever goal she strives toward.
- Moana: Te Fiti, the Mother Island, is a larger-than-life goddess who gave life to countless islands in the world. She is covered with moss and plants, and can make plant life grow from anything, even ash and soot. She is a kind and benevolent goddess, until her Heart is stolen and she transforms into the destructive Te Ka.
- The Cthulhu Mythos has Shub-Niggurath, the Black Goat of the Woods with a Thousand Young, a decidedly dark take on this. Procreation, sex, and nature fall under her purview, but she's still as much of a God of Evil as any other Mythos deity, requiring Human Sacrifice deep in The Lost Woods on the night of the full moon, as well as foul and depraved orgies, usually with her or one of her Dark Young taking part in the form of a satyr. That is, if she hasn't shown up as a cloud of monster-haunted black fog, or a full-blown Eldritch Abomination.
- Discworld: Gods tend to merge with each other across different cultures due to the way belief works on the Disc, so it's explained there's only one fertility goddess with a very large collection of wigs and padded bras.
- In N. K. Jemisin's Inheritance Trilogy, Enefa was the Goddess of Life and Death, and, as a co-creator of the universe, the inventor of those concepts. She was described as a maternal figure to the lifeforms she created, but nonetheless destroyed them without hesitation when she felt they'd served their purpose.
- Kushiel's Legacy: The d'Angeline goddess Eisheth (who, like all of Terre d'Ange's gods, is a former archangel of the Abrahamic God who left heaven to follow Elua) provides Fantasy Contraception to the women of Terre d'Ange, which is quite important in their culture. Women who wish to conceive pray to her to open their wombs.
- The Redemption of Althalus: Dweia is the goddess of love and fertility in all their forms, from agriculture to childbirth, and mediator between her Creator and Destroyer Deity brothers. Nonetheless, she's a bit put off by one culture's depiction of her with extreme Multiboobage.
- A Song of Ice and Fire: The Summer Isles worship a goddess of love, beauty and fertility as their most important deity. Sex, lovemaking and procreation are all considered holy within the Isles' culture, with prostitution even looked upon as a treasured profession that even some high-born natives aspire to.
- The Goddess of Life from Tasakeru. Usually appearing as a beautiful (in a couple of myths, the most beautiful) female of a given race (of which there are a whopping 9; 11 if you count near-or recently-extinct races), her purview is life, crops, fertility of all sorts, and the wellspring of Magic. Her husband is the Time god, and their mutual rival (both in love and war) is the Death god. Specific myths point her out as singularly beautiful and capable, and as a mother figure to all life on the World.
- Supernatural: The brothers end up facing a Vanir, a Norse Fertility God, in "Scarecrow". Brought over to America by Scandinavian colonists, the town of Burkitsville entered an agreement where each year they would provide it with two blood sacrifices, and in return it would ensure its blessing fell upon the town, granting them constant bountiful harvests and sparing their town from financial struggles. The Vanir itself manifests in the form of a Scarecrow. It's killed at the climax when they torch its sacred tree, brought over from the old country as a sapling, that was the source of its power and tether to the world.
- Classical Mythology:
- Demeter (aka Ceres) is the most archetypical fertility goddess, being the deity of agriculture and harvest. Her most famous myth involves her daughter Persephone being married and/or kidnapped by Hades, thus making Demeter miserable and causing a winter where plant life begins to wither and die off. In some tellings, this is merely a result of her mood, but in other versions, Demeter intentionally does it to essentially hold life on earth hostage. Either way, Zeus eventually intervenes and allows Persephone to return to her mother for half of the year (Spring and Summer) before returning to the Underworld for the other half (Fall and Winter).
- Persephone herself is either a goddess of spring and vegetation, a goddess of death and the underworld...or both. Her exact tasks in either role are relatively unknown. As a fertility goddess, some hypotheses posit that she and Demeter must somehow work together, and as the goddess of the underworld, she was sometimes referred to as "Dread Persephone" with some even too afraid to say her name. She is sometimes also portrayed as a compassionate death goddess who made sure the recently-deceased were properly venerated and buried, and who had their needs taken care of in the afterlife. The latter case possibly explains her somewhat contradictory nature.
- Heracles was often worshipped as a symbol of male fertility and virility, usually within the context of men siring strong heirs or sons. Heracles himself was accredited with having hundreds of children from dozens of different women, who were referred to as "Heraclids". For example, most Spartans claimed ancestry from Heracles. He was also known for having passionate sexual affairs with various men as well, which was also celebrated as a form of male virility in Ancient Greece.
- In addition to love, sex and beauty, fertility was sometimes considered part of Aphrodite's purview, although that was mostly due to her association with the Roman fertility goddess, Venus, and the Mesopotamian goddess Astarte. Nonetheless, her myths were also full of children that were born in very short order after Aphrodite used her powers on one (or both) of the parents, and Aphrodite herself also had a large number of children as well.
- Egyptian Mythology: Hathor was the Ancient Egyptian goddess of music, beauty, love, sexuality and fertility. Her "positive" spheres emphasized feminine and procreative energy; some myths state that she helped create the world, often by giving birth to it herself. She was also the most beautiful and usually considered the most sexually-enticing of the gods, commonly using her sexuality to solve (or create) problems.
- In Igbo Mythology, Ala is the goddess of fertility and considered the Top God of the pantheon. Not only does she hold dominion over the earth and mortality in general (her name literally translates to "the ground"), but she is married to the sky god Amadioha, and her womb is where the underworld and the afterlife dwells.
- Japanese Mythology: Inari is the god of agriculture, fertility, rice, tea and sake. They (Inari is alternately presented as male, female, and ambiguous) are one of the most important and celebrated of the Shinto mythos, often considered a guardian and protector for mortals. They are also highly associated with foxes, with all foxes considered Inari's messengers.
- Mesopotamian Mythology: Ishtar (also known as Inanna and Astarte, and also considered the antecedent to Aphrodite) is known as one of the Mesopotamian deities associated with fertility, along with war, love and sex.
- Norse Mythology: The Vanir gods, one of the two rival factions which later integrated, are usually stated to be associated with wisdom, health, foresight and fertility. These included Njordr, the god of seafaring, wealth and crop fertility, and Njordr's children: Freyr, who was the god of virility, peace and prosperity, and Freyja, who is one of the most important gods of the Norse pantheon, being the goddess of war, sex, love, beauty, gold and fertility. She is associated with rye fields (which Scandinavians heavily relied upon).
- Zoroastrianism: Anahita is associated with fertility due to being the yazata of rivers. She is believed to be derived from the same proto-Indo-Iranian goddess who gave rise to Saraswati, and during the first Persian Empire she was syncretized with Ishtar.
- In Christianity, the patron saint Andrew the Apostle is viewed as something as a lesser deity to Catholic believers. He is usually acknowledged for being the patron saint of fertility and pregnancy.
- Dungeons & Dragons:
- Forgotten Realms: Chauntea is the goddess of agriculture, and one of the most popular deities among Faerunian commoners. Her followers often claim that she is the progenitor of all the mortal races, and her major holiday Greengrass is essentially the Celtic holiday Beltane with the serial numbers filed off. Other fertility deities include Shiallia, Sharindlar from the dwarf pantheon, Aerdrie Faenya and Angharradh from the elven pantheon, Sheela Peryroyl and Yondalla from the halfling pantheon, Hathor, Isis, and Osiris from the Mulhorandi pantheon, and Luthic from the orc pantheon.
- Eberron: In the faith of the Sovereign Host, Arawai is "Sovereign of Life and Love", and is patron of agriculture, life, and fertility. Curiously, she is also said to be the sister of the Dark Six god of destruction the Devourer, whom civilized folk often also pray to for protection from flooding and drought.
- The GURPS "Dungeon Fantasy" sub-line features classic dungeon fantasy-style clerics and holy warriors, and allows for the possibility of them worshiping a range of deities. Specifically, GURPS Dungeon Fantasy 7: Clerics offers different spell lists and special powers for different types of deity served; it covers "Gods of Love and Fertility" in a single section, assuming that the two domains are likely to be linked.
- Erastil is the patron god of rural communities, family, agriculture, and hunting. He is also husband to Jaidi, an ancient Azlanti agriculture goddess; together they are parents to Halcamora, a demigoddess who specializes in parks, gardening, and wineries.
- On a darker note, Lamashtu is revered in some cults as the "Mother of Monsters": an Evilutionary Biologist who likes nothing better than to bring new and vile monsters into existence to set them loose on Golarion. She's seen as a patron goddess by many goblinoids.
- Nurgle, one of the Chaos Gods from Warhammer 40,000, is essentially a twisted version of this trope. His domain is fertility and life, but, the universe of Warhammer 40k being what it is, he is most closely associated with decay and disease. After all, bacteria and fungi are living things too!
- Warhammer Fantasy: Rhya the Earth Mother is worshipped as a goddess of life, birth, growing things, and the gentler aspects of nature, and counterpart to the more violent nature god Taal. Her cultists often serve as midwives in remote areas, and one minor sect worships her as Dyrath, a goddess of fertility and womanhood.
- City-Building Series:
- Pharaoh: As god of the Nile, Osiris is responsible for the fertility of floodplain farms, making them barren, withholding the Inundation or even destroying the farms if displeased, or making them double their production if prayed to. Constructing his Temple Complex also allows wood and papyrus to grow back faster.
- Zeus: Master of Olympus:
Heavens! There aren't nearly enough people in the city to worship me!
- Demeter's Sanctuary turns all the land around it to meadow, on which livestock, crops or farms can be placed. She'll also bless farms and can fill granaries with food if prayed to. She's also the fourth most-powerful goddess after the Big Three, so having her around can thwart quite a few invasions by other gods. Naturally, having her as an enemy will cause a lot of problems for agriculture-based cities.
- Gods associated with a particular foodstuff (Poseidon for seafood, Artemis for wild game, Hera for oranges) or trade crop (Dionysus for grapes, Athena for olives) will bless their particular industry, making it more productive, and can provide large amounts of it when prayed to. Hera, Dionysus and Athena also provide groves for their crops, allowing your city to harvest a small amount every year.
- Aphrodite isn't a fertility goddess in the usual sense (population only increases through immigration if you have the housing for it), but if you've suffered a massive population loss due to disease she can instantly replenish your population... for less than heroic reasons.
- Emperor: Rise of the Middle Kingdom: Shen Nong the Divine Farmer is one of the three Ancestor Gods, who can bless farms if kept sufficiently happy.
- She only gets a brief mention in the Dragon Age: Inquisition DLC Jaws of Hakkon, but Rilla of the Fireside is the Avvar goddess of "making babies." They appeal to her specifically when they're trying to have children.
- Some deities of Dwarf Fortress can be generated with Fertility among their spheres.
- In Fire Emblem Gaiden, Mila is the Patron God of Zofia, keeping its lands constantly fertile and overflowing with life as a source of comfort to the humans living there. Because of this, she has a devoted following of worshippers who praise her as the Earth Mother. But her gifts have also made many Zofians slothful and hedonistic, as shown by the debauchery of the king before his assassination.
- Horizon Zero Dawn: While GAIA as a whole was created for this basically an A.I. tasked with recreating an entire biosphere after a global extinction event, the specific functions that helped nurture life in the new world were DEMETER, which recreated plant life, and ELEUTHIA, which created human beings and gave them a very limited early education.
- The Legend of Zelda: Of the three omnipotent Golden Goddesses that created Hyrule, Farore was the one who created all of the life. Though she is mostly known as the Goddess of Courage, and is specifically the one who blesses and empowers the chosen hero, her other blessings and sacred relics may also help various forms of life flourish.
- Touhou: Minoriko Aki is a goddess of the autumn harvest, able to curse or bless harvests made at that time. The Human Village calls her up for the harvest festival to remain in her good graces.
- RWBY: The God of Light is, as his name suggests, the deity in control of light and life. He creates plants, water, and wildlife, and often opposed his brother, the God of Darkness, who brings destruction. He and his brother later came to a compromise, and together created humanity.
- Lore Olympus: Fertility goddesses are born roughly once every generation, and are notable for their ability to bear children who are considerably stronger than their fathers and tend to overthrow them. The protagonist of the comic, Persephone, is this generation's fertility goddess, even though she has no idea, as her mother made sure she had no contact with men and joined a chastity cult. She was not unjustifiably overprotective, though, since as soon as Persephone enters the outside world, she immediately becomes a target, leading to Apollo raping her in order to pressure her into marrying him. The fertility goddesses before Persephone included Hera, Queen of the Gods, and her and Zeus' mother Rhea.
- The Order of the Stick: In a Flashback, we see Thor being chewed out by Loki for having impregnated another goddess (presumably from a one night stand), without noticing that the woman with flowers spawning around her feet and bluebirds flapping around her hair is a fertility goddess.
- Girl Genius: Ashtara, the patron goddess of the lost city of Skifander, is a fertility goddess. According to Zeetha, Skifander's holy days are a lot of fun.