The normal theory is that you take genes from both your parents and become a real person, but I have to try to challenge it a little because some animals just sort of changes gender and become a girl to foster the children, so with that in mind, do we humans really need to have both parents to make one? I believe no, because I think a spermie is actually fully developed in the male body, the life or children just get`s transfered to the girl for her to foster it because they`re naturally very caring, giving it air and food and somewhere safe to be, the reason I think we look like both our parents are because of love, you like and adore your parnents sort of so you try to look like them, which brings me next to what dna really is for, I think the soul just makes the dna-strings so the cells knows how to make themselves over and over again without the being actually doing it everday, that`s why sometimes there`s a mistake in the strings or kinda quite often actually, so we have the actualy ability to create the strings ourself and it`s just an representation of what we are sort of bodily, the soul is not dna I think, but the body, that`s why if you for example clone an animal, it still has a unike soul that didn`t come from it