Sexual health foundations

I’m interested in doing volunteer work (I know the problems associated with the legalities of this, but think that I can get a work permit). The area that I’m most interested in doing this in is sexual health/family planning. Does anyone know of organisations that work in this field, would welcome volunteers and are open to foreigners?

I’m not really interested in organisations that preach abstinence. I know some people think this is the way to go about it, but it’s not the way I want to go about helping people.