This paper explores some aspects of male identity formation. Conception is used as the starting point of human development, and the implications are discussed for male identity development of female and male development being the same for approximately the first trimester, and of both female and male spending the entire gestational period as a part of the female, maternal body. Relative maturational and developmental rates and trajectories in the female and the male are discussed as well. It is noted that by early childhood the male has potentially undergone a greater number of, and less continuous, developmental processes than the female. Both prerequisites for and consequences of the inherent discontinuity in male development which proceeds to masculine identification are examined.