I'm with Asuka on the no-kids-for-me thing, and it drives me nuts that I can spend ten minutes laying out a long list of reasons why I am not going to have kids -- finances, mental health, physical health, family history of mental and physical issues that have only worsened with each generation, personal inclination -- and the response is invariably "you'll change your mind when you're older (you silly girl, you couldn't possibly have thought this out and made the responsible decision)". Meanwhile, my male cousin, who is ten years older (and physically and mentally healthy, with a good job, etc.), needs only to say "I don't want any" and the subject is dropped.