When people who shouldn't have kids have kids. Similar to procreate, only in a negative sense.
Wow, I hate seeing pregnant 14 year olds. It's a shame to see young kids concreate.
by Mouse Killing Spiders September 7, 2007
People who are in no way able or prepared to have a baby.
Procreation is for a couple who is planning on such situation. Concreation is either people who didn't plan on a child or by certain standards.....shouldn't have a baby.

Karl, your sister just had a baby! Congrats!

Yeah well, she's dumb as a rock and I fear for the baby's upbringing.
by SSBrando March 27, 2010