Why do women care so much about your personal business and whether you're single, have kids, are married, etc.?

Shit, it seems like any time I deal with women they can't stop asking personal questions about your life. When you tell them that you're single they can't stop trying to give you advice about getting married and having kids, some bring it up over and over. They can't seem to understand that there are some people that don't want to be in a relationship or have kids.