Neonatally castrated (NC) 51 male Long-Evans rats and divided them into 6 groups. A control group received no perinatal treatment. The remaining groups received 200 MUg. of testosterone proprionate (TP) on 2 successive days (Days 1 and 2, 3 and 4, 5 and 6, 9 and 10, or 13 and 14 of life). As adults, Ss were given estrogen and progesterone and tested for feminine behavior. Subsequently 5 Ss from each group were given daily injections of TP and tested for masculine behavior. The most complete and intense feminine behavior was shown by the control group and the 13- and 14-day group. The 1- and 2-, and 3- and 4-day groups showed the most complete masculine behavior. Ss exposed to TP before Day 10 had the largest, heaviest, and most extensively cornified penes when treated with TP as adults. Neither the behavior nor the morphology of the NC Ss equaled that of intact males. (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1969 American Psychological Association.
