Why does Ikuto insist that it's the man's job to protect the women from the island's dangers, despite being significantly outnumbered and less strong, competent, and knowledgeable about the island than anyone else? He is severely endangering the colony's long-term survival prospects with this attitude, being the only male and all.
Probably some cultural thing. Besides, one male isn't enough to continue the community into future generations (too small a gene pool: the whole next generation would be siblings or half-siblings).
Well, grandma's scientific knowledge is centuries outdated, so she gets excused for her terrible idea. It remains a mystery why Ikuto hasn't pointed this out himself, though.
Maybe he just wasn't taught genetics before being stranded. And yes, It actually could work, with careful planning. Take any male offspring and have them mate with any older female that is not their mother. Then you have cousins, and real life cousin intermarriages usually produce, fine, healthy children. Like Albert Einstein, he married his cousin and had perfectly healthy, non-defective kids.
And how old would these "older females" be once you get those male offspring? Anyway, successive pairs of cousins wind up being just as bad. A single male is simply not enough; there's no way to get around it. Enjoy your freaky mutant babies.
Given the apparent age of Ikuto's most likely romantic prospects, and assuming he gets started soon, any sons would be mature well before the members of Ikuto's harem hit menopause. Remember, they aren't blood relations of any of the women currently on the island besides their mom, so Ikuto's sons could bang the rest of his harem with no worries.
You don't have to know squat about genetics to figure this out. If all the new children have the same father, they're all going to be siblings or half-siblings. Even if you do the cousin thing (eew), they're all going to be too closely related.
Genetically first cousins are just as safe as perfect strangers! So careful planning can work out fine, if he started with in the next few years with enough woman to get enough sons to get make sure the problem dies out.
Indeed, not all the offspring would necessarily have the same father. For example, if Ikuto and Suzu/anyone had two sons, then - with age - each of the sons could have a child with another unrelated, older female of the island, as suggested by an earlier troper. Granted each couple has a child of a differing gender, that would make the "cousin thing" feasible. Not to mention, if Ikuto had multiple partners as well, that would allow for a larger, more complex lineage tree, but allow for a more versatile population growth. Finally, it's only suggested by mainstream culture that blood-relative incest is a bad thing, and while I agree that the odds of an unhealthy birth are much greater than normal, it is not impossible to produce fully-capable children from sibling parents.
Of course. Plus we have a real world example from two sources, Egypt during the reign of the Ptolemys who married siblings for over 300 years! and still had decently healthy offspring, the nation of Egypt today isn't any worse genetically for having practiced incest for centuries; and the Ostrich People (google it) also called the Doma or Vadoma of Africa which are a tribe that shun outsiders so much they've practiced incest for THOUSANDS of years. At worse incest on the island would be limited to a few generations before reestablishing contact with civilization. Even if not it wouldn't be so detrimental to them that suddenly they'd all turn into circus freaks just because their parents are brother and sister spanning back generations.
How can an island be completely surrounded by whirlpools? Not only are whirlpools like that impossible in and of themselves, but there is absolutely no reason why they should surround the island.
Why doesn't Ikuto like the idea of, you know, being wanted by nearly every women on the island? Being pursued exclusively by dozens or hundreds of beautiful women should be a dream come true.
Got me there. Kinda like Please Put Some Clothes On. On second thought, there wouldn't be as much conflict (therefore, no plot) if he lived like the sultan of the island with his personal harem.
The idea that guys who don't enjoy the idea of being wanted by every woman around him is an idiot always ticks me off. I mean, just look at what happened in School Days...
Seriously how would you handle the situation? I would be terrified. It would be flattering, but how could one choose with out fear for ones life? All of the woman are super strong, and many are very well trained. Quite a few have already used varying tricks and degrees of violence to get their way.
This is the boy who loses about half a liter of blood just by seeing some breasts. He could not handle actual sex, hell getting to second base makes him lose so much blood he passes out. Death can be a very good motivator.
He also is dense. Really dense. He still thinks everyone is after him because he is the only guy in the island, while the whole female main cast, the principal offenders being Suzu and Machi had already shown very explicitly that it is not like that anymore.
If nothing is impossible, then why can't supernatural shit exist?
Or he just believes that nothing is impossible for him, other people and the natural world on the other hand...
It is revealed later that his family put some seal/spell/whateverish thing on him that caused him not to notice the supernatural things so that he would not notice that his (non-blood-related) sister Misaki is part-youkai.
In the scene where Ikuto realizes that he can talk to the animals after receiving a basket of eggs from the mother chicken, this troper had a different epiphany. How come this very human-acting chicken, with at least two chicks of her own, is willingly giving her unfertilized eggs to be eaten? Wouldn't that be like a human mother working at a lemonade stand, only the lemonade is her menstrual periods?
The chickens obviously practice Christianity or some other religion that causes them to believe that life begins at the embryonic stage.
Technically speaking, chickens won't get born out of eggs that weren't fertilized, so it's like asking why a menstruating woman is killing her children every month.
Just started (so maybe it's explained later?) but uhhhh, how is Yukino 11? The men all disappeared 14 years ago! The youngest person on the island could only be 13 if her mother was pregnant the day the men left.
Unless it was a case where the author had a flip flop after forgetting about that detail, we can assume that she is in fact 13 but her own... dimensional deficit made her think that she is younger than that (just look at Suzu, she's pretty much the youngest [let us ignore Tsukino for a moment] and she's kind of well-developed for her age) and everyone else just went along with it.
Where is it said they disappeared 14 years ago? The first page of Chapter Three says it was 12 years ago.
Chapter 105, near the end. Ikuto was inside Mei-Mei's house, the scene cuts to his younger sister Misaki, then cuts back again to Ikuto, Machi, Ayane(who left moments ago) and Suzu!? What.