Putting Feminist Theory Aside For The Moment...
Biology clearly has a part to play.
Of course, this is also about how quickly rrrowwwllll can turn to awwwww!
Boobs and new baby smell. Two of the most viscerally amazingly wonderful things. I have found over my lifetime that it's far, far better to make positive sense of them, rather than try to argue with myself or with others that that viscereal sensation is some subtle snare of the devil.
"There is no sin but that thinking makes it so," and as far as I'm concerned, this is a great illustration of "Honi Soit Qui Mal Y Pense."