I'm in need of your wide learning.
A few months ago I was reading Steven Rhoads's Taking Sex Differences Seriously. Somewhere in passing (meaning in just a couple of lines) he says that boys who buy condoms rather than rely on free sources were much more consistent and correct in their use.
I have lost track of my notes and having looked though the book twice it seems this is a needle hiding in a gray rug. A try at google regular and g. scholar doesn't quite return what I'm seeking. I suspect I'm not getting the search terms right.
Any clues where else to look or more unique research terms to try?