It's where a woman, usually one that is unprepared to be a good educated provider and parent, wants to get knocked up or pregnant. Generally this happens when puberty hits a young woman and they get the silly idea in their head that having a baby will fix all their problems, when in fact it is just their hormones going crazy.
The woman generally will attempt to have sex with a unsuspecting male, who then will become entangled in a baby mess that he had no plans to deal with.
Jake: Hey guys, there is a nice looking girl, did you ask her out?
Mark: Oh no dude, she is totally kid crazy, stay far away from her unless you want to ruin your life. She will pull off your condom and tell you she is on the pill, then 9 months later your a Dad. Forget college and a career man, you will be working at Mc Donald's trying to support your baby, just like David who got with that hoe Kimberly.