>>82391759 (OP)
Because it's a benefit to them.
You either don't see it as a worthy benefit, or your morals prevent you from having children.
People always had children because it benefit them, times are more peaceful now so we're more liberal than ever, but picture that you're some random peasant about a thousand years ago with nothing but the small amount of farmland you own, You'd have a child simply for extra helping hands on the farmland.
Guys want to have housewives so they don't have to cook and clean themselves, isn't that selfish aswell?