in all reality it comes down to the basic instinct to reproduce, and the instinct to want something of your own to love. but you could also claim the fact that kids are cute, fun, and a wonder to watch grow up.
To have someone who would take care of them when they get old.To carry on family name. Because they love babies. It's human nature.To let their children (who don't exist yet) experience the joy of existence.To give parents grandchildren.To embody love for each other. Or because They don't know. Some people just say they don't know as if creating a new life is not a serious issue. They just don't think about it. Other people are doing it so I will, too.
Stupid teens think its cool to get a girl pregnant. If your gonna get pregnant or get someone pregnant at least be a good parent. Why would you want to give someone life but not be their when they need you? Don't ruin someone's life especially when they're young
Some people wants children because its part of there religion to have offspring. Like Christians for example, the bible says that God tells them to have many offspring. Others may just like children and want to care for there own.