Biologically-based qualitative differences between the sexes define the natural distinctions that differentiate male and female. The male possesses a penis; the female, a vagina and breasts. These anatomical differences are the foundation for functional divergences which possess profound psychological import. The psychological import arises from the natural potentials and constraints that are associated with anatomy.
The anatomical differences between the sexes provide a set of fundamental constraints on social adaptation. Men impregnate, women become pregnant. Men may impregnate multiple partners simultaneously or successively. Through this activity, the male can see himself in his progeny mirrored in the form and frame of multiple partners with no limit to the number of offspring, with little reproductive labor except as realized in coitus, and with no upper age constraint on impregnation. He does not bear young within his body and does not suckle young by the agency of his body. In contrast to the female, he possesses a remarkable freedom from biological constraint. He may impregnate multiple wombs.
The natural potentials and constraints associated with anatomical sex may be contrasted with social “constructivist” explanations of sexual difference. Social explanations locate psychological and behavioral differences in social roles, expectations, and social learning. Although the assumptions that ground these two approaches are radically different and the two approaches may lead to radically different conclusions about causality for the same attitude or behavior, the approaches are not inherently opposed, but complementary. The approaches are complementary because humankind is circumscribed by both biological and a social factors. The determination of sexual difference is not in biology alone or social factors alone, but in their interaction. Although this assertion is generally accepted by reasonable people, its import is often quickly set aside as one or another disciplinary perspective prevails. Behavior is understood only from the biological or the social point of view. The justification for this one-sidedness is consistency of argument, the existence of arbitrary disciplinary boundaries, overt of covert agendas, or their mixture. Unfortunately, one sided approaches completely miss the interaction that occurs between the biological, social, and psychological. In the deep sense, there is no biological determination alone or social determination alone, but always these determinants operate in mutual relation. The attribution of sex differences to biology only or social learning only without regard to their interaction falsifies both.
No matter how sex differences are rationalized by social constructivists, females do not impregnate and males do not become pregnant. The regularities that govern sexual attraction, evolved through evolutionary selection, remain intact. Youth is preferred to age; health to impairment; strength to weakness. No matter the social ideology, personal appearance and attractiveness are among dominant individual preoccupations and expenditure. When ideology suppresses masculinity and femininity, the relations between the sexes lose their fire and delight. Culture loses its zing. Half-truths prevail, and vacant bureaucracy destroys harmony.