The people within this age range most likely want a baby for themselves/want more babies, or they don't feel like they should have to be limited to the amount of babies they want. Since it is their life and their bodies, they think it is up to them to decide how many to have and whether to have one or not.
The reason is because of the theory "the path of least resistance." The bird is not touching anything else, so it doesn't become our fried birdie dinner.
