Education has a lot to do with it as well
I went to a private high school from 9-10th grade then transferred public.
similar in size, different in demographics
At private school we didn't have a single pregnant girl.
Public school? Sheeeetttt they were everywhere?
Education and income are linked. In general, more education equates to better paying jobs. This is OVERALL, not in every instance.
Anyway, you're confusing the two points being discussed. Just because the private school student doesn't have children, it does not mean they are having less sex than the public school student. The student from private school may be having more sex, they may just be using protection. The kids from public school can have sex one time and get pregnant and then have sex only sparingly.
What I am saying is the amount of kids one has does not automatically mean they are having lots of recreational sex. They may only have sex when they want to have a kid. Whereas, the two people with more money may be having a ton of sex, just using the appropriate protection.