"The emotional side is different - mothers are not supposed to "unwant" their children. Most generally experience hormonal changes in pregnancy that nurtures the instinct to love and care for their children."
I don't mean this to sound condescending, please believe me, but this statement is fairy tale like. Forever and a day women have been saddled with children they do not want. Pregnancy does not conjure up some magical love potion, in fact, it's been known to invoke quite the opposite. Giving birth does not a "mother" make. Many mothers do not feel an immediate love for their newborn and the stereotype you describe can be the cause sometimes, I think, of a new mom being unwilling to admit she's exhausted, or just plain "not feeling it" because of the pressure to be this perfect maternal model. It's funny actually, the "rainbows and unicorn" label given to adoption can easily be applied to the act of giving birth and the euphoria and love that's expected to be automatic and "natural". Being a new mom is damn hard work and any chance I get I'll tell them to accept the feelings of exhaustion, that it's ok to feel like you want to chuck your baby out the window because they just won't stop crying and you haven't slept for days. It's when new moms have to pretend these feelings don't exist or that they feel pressure to hide them that they end up doing things I don't even want to go into here.