Many do not want their names to 'die'. They must have a child , especially a male child , to keep their names for generations. Well, we do not know any of Achebe's, Einstein's and Shakespeare's children. But these people are immortal. Every time you teach students algebra, you must mention Pythagoras; whenever you teach students Enzymes, you must mention Leonar Michelis and Maud Menten, and so on. Generations will call their names around the world for thousands of years and we don't know about their children.
If you haven't done anything, whose son or daughter will your child be even if he/she is the next Dangote? Okeke the son of who? Do not think that you have done enough by having and raising children and in the process end up contributing nothing personally to your world.
You don't get remembered because of your sons and daughters or your mansions or the wealth you have gathered up for yourself and for your children and children's children. You get remembered by the works you have done. Your children will be remembered by the works they have done. Doesn't even a religious hymn say that already!