A close friend has unexplained infertility after one child. People at work still ask her why she hasn't given her daughter a sibling, and when told she's trying (for five years), they then tell her to stop trying so hard.
Women's fertility and choice is under constant scrutiny, mostly from fellow women. I wonder whether it's simply to validate their own choice, or a genuine disbelief that some people want no/one/five children.
My own mother told me I should try and have a girl after this one (third son) moments before acknowledging I have horrible pregnancies. Reality doesn't seem to come into speculation about babies.