Abstract22 unwed fathers and 22 unwed nonfathers, all wards of the California Youth Authority, were interviewed, (a) More unwed fathers than nonfathers were illegitimate (p<.01) and (b) had siblings with illegitimate children (p<.001). (c) More siblings of illegitimate Ss than siblings of legitimate Ss themselves had illegitimate children (p<.01). More unwed fathers than nonfathers approved (d) of their own children's becoming unwed parents (p<.001) and (e) of extramarital sex (p<.001), but disapproved of (f) the use of contraceptives. They felt (g) responsible for pregnancies they caused (p<.05), (h) said they would marry a woman with another man's illegitimate child (p<.001), and (i) felt that their children would not be affected by their behavior (p<.001).