> It's somewhat surprising that younger ages, especially 18 to 25, do not have this effect Not really. My hunch is that it's due to two reasons: (1) education

> It's somewhat surprising that younger ages, especially 18 to 25, do not have this effect Not really. My hunch is that it's due to two reasons: (1) education is often much less intensive than a competitive career, so it's much earier to study while having a child (in many cases, you don't even need to attend the lectures, just pass the exams!); (2) probably the much bigger reason is that the "have children before 25" sample includes mostly people in non-professional careers where there isn't a lot of room for advancement anyways... someone with 2 years of experience as a store clerk or receptionist is worth about the same as someone with 4 years of experience, whereas the worth is significantly different in something like medicine, investment banking, programming, ...