Children are not good investment.
They have the biggest return on investments. Calculate how much you spend on each child. Some families have 5 or 6. 20 to 30 years later, they each make maybe 50k per year so 300k total, if you took care of them. More if they are smarter than you. Not counting all the fun you should have had all that time, (and all the problems too, of course.)
If you live to be a grand parent, well, they say they have the greatest joys... 10+ grand kids who you don't have to take care of at night, just play with them during the day. Unless you're still supporting your children (and grandchildren) because they suck. Well, that's partially your fault.