176 adolescent adolescentbehavior adolescenthealthservices africa birthcontrol casestudies contraception control counseling ethics fertility formal geneticengineering history human humanreproduction humanreproductivetechnology marriage medical moralandethicalaspects prevention preventivehealthservicesforteenagers psychology psychosexualdevelopment publicpolicy reproduction reproductivebehavior reproductivetechniques schoolhealthservices sexinstructionforteenagers sexualbehavior sexualethics sexuallytransmitteddiseases socialaspects socialconditions socialcontrol socialserviceandsex socialworkwithteenagers sub-saharan teenagegirls teenageparents teenagepregnancy teenagers trends unitedstates wq205w984s1990 ws462 ws462a23881989 ws462n275d1991 ws462z12a1993