It may help to consider that, while an egg is a chicken's way of making another chicken, equally valid you may view that a chicken is an egg's way of making ano

It may help to consider that, while an egg is a chicken's way of making another chicken, equally valid you may view that a chicken is an egg's way of making another egg. Follow this train of thought, we can imagine that reproductive morphology is there for it's own sake. The genes that create it, are successful if they create creatures that propagate those genes. Never mind how onerous it is to the creature. Sure, they can't cause the creature to actually expire in the effort. But short of that, they can get as strange as galapagos birds and so on, purely for their own sake.