Subverted: David has multiple parents and seems to inherit a lot of their traits, but only two are, in fact, biological.
Double Subverted: ...And then it's revealed that the other parent(s)' traits don't pass down genetically, but through life force or memory or something of that sort. David was partially conceived by them without a doubt, but not in a method most humans would understand.
Zig Zagged: Alice, Bob, and Charlie all confirm and deny being David's parent at a given time, and genetic testing is inconclusive.
Averted: Human DNA turns out to be incompatible to Charlie's race, and conception is impossible.
Enforced: There's been a Love Triangle going on between Alice, Bob and Charlie for some time, so the execs decide to solve it by having the three of them conceive David so they decide that all three have a relationship.
Lampshaded: "Charlie's species just happened to have the right genetics to allow all of us conceive a child! Isn't that amazing?!"
Invoked: It's a Free-Love Future, and two-person couples are now ancient history. In order to support this new dynamic, scientific breakthroughs have created a third, fourth, or even fifth sex to produce offspring.
Exploited: Both Alice and Bob want Charlie, but know that Charlie's species can reproduce with any number of mates, so they decide to join forces in seduction.
Defied: Despite living in a Free-Love Future, Alice and Bob are soulmates and are sure that their baby will be just fine with two parents.
Right after "the bussiness" has been done, this happens...
Charlie: You know, my species can mate with any number of partners. Alice & Bob: Reeeeeally?!
Alice, Bob and Charlie are a menage a trois, and wish that there were a way to conceive a child with all their traits.
Deconstructed: David inherited not just all of the good traits that come with each parent, but the bad as well. He's born with the Type 1 diabetes inherited from Alice, weak bones from Bob's side of the family, and Charlie's species is sometimes has a rare disease that makes plant chlorophyll allergic.
Reconstructed: ...But despite all of that, David eventually gets past all of his deficiencies to live a wonderful life. Also, his unique genetic heritage has helped open the door for many medical discoveries.
Played For Laughs: David has just arrived in Orgyburg, and everybody he meets treats him as a son, including the animals.