CMV: Childfree women who don't want to be involved with kids are judged more harshly than childfree men

It seems to me that women are judged more harshly than men when it comes to their decision to not be around kids. If a man says he doesn't want to be a dad or be around children, he is usually just left alone. But if a woman says she doesn't want to be a mom or be around kids, she is judged. People usually try to change her mind or say she's being selfish. Why?