A basis for the following is provided in Human Origin.
Even Ayn Rand cannot overcome mate selection with reason, because much of mate selection is biological. It is driven by gene and immune system selection for progeny viability. Today intellect may not elicit a superior mate, but to the degree that intellect begets wealth, which is perceived as security by females, it is preferentially selected. Wealth can also be had by the ruthlessness or cunning with force or fraud. One cultural norm that disrupts natural selection is arranged marriages.
Past/Present Present/Future Testosterone affects masculinity. The more testosterone, the larger, stronger and more aggressive the male. In the primitive world, this meant more food, security and viable progeny. Females moving on arms and legs could carry progeny on their backs. For upright walking females attempting to carry two children or a child and supplies, a strong mate was essential. A more intelligent male will likely provide more food through the trade of his excess productivity. With a tool like a gun, a weak male can provide as much security as a strong male. He will likely contribute to more intelligent progeny, which will be more likely to thrive in a non-violent world of free-trade, particularly a world without government or religion. Dissymmetry occurs in the womb due to small genetic abnormalities, so symmetry correctly indicates genetic health. Plastic surgery can correct dissymmetry, and provide false clues about genetic health, resulting in less viable progeny. Estrogen and Progesterone affect femininity. The more of these hormones, the more curvaceous and properly proportioned is the female for child birth. Plastic surgery can correct some of the unattractive features, and provide false clues about motherhood suitability, resulting in less viable progeny. During ovulation estrogen and progesterone increase, causing skin to clear and flush, lips and breasts to become more prominent and the posture and walk to be more enticing. Regardless of age, males find fertile females, particularly ovulating females attractive, which is why men become "dirty old men." Appearance artificially altered with make-up, structural underclothing and high heals can trick men into attending to non-ovating or even infertile women. Gonads and brains develop at different times in the womb, so physical and mental sexuality may become incongruous during fetal development if hormone levels are incorrect, especially during the third trimester. Excess testosterone in the womb caused by stress or other factors may wire the brain of a sexual male to prefer other males or the brain of a sexual female to prefer other females, i.e. be homosexual. Very female brains may resort to make-up, long hair and female attire to disguise their male physiology. Very male brains may resort to short hair and male attire to disguise their female physiology. Extremely female brains may resort to changing their gonads and breasts to resemble those of females. Extremely male brains may resort to changing the sexual physiology of their body from female to male.
Although homosexuality is abnormal with regard to procreation, it is natural and common to many species for procreation reasons, because not having progeny is one way for a population to relieve sustenence stress. Homosexuals will not increase the stress by procreating.
Females will control their hormone levels during pregnancy, and thereby chose the sexual preference of their progeny. A favorable body oder indicates a complementary immune system, which will result in more viable progeny. An unfavorable aroma indicates a genetic relative with whom progeny will be less viable. This sense is particularly heightened within two days of ovulation. If the MHC genes of mates are similar, spontaneous abortions will occur, because their immune systems are too similar.
Perfumes, deodorants and lotions provide misleading indicators that will result in less viable progeny. Given the dependency of females on others during and after pregnancy, a major selection criteria is security. About 10% of those who have selected a mate based on security have sexual intercourse during ovulation with more masculine males to get the best of both. In an easy-credit society, males can lease or rent vehicles, clothing and housing to fool females into believing they are good providers. In a welfare-dominated society, females are less likely to select males on the basis of security, or enter a long-term relationship with any male, because taxpayers are forced to provide the security, education and care a father would otherwise provide, so masculinity will be selected over intellect, making progeny less viable. Many females divorce after four years of marriage. This is likely because a child of three years no longer needs to be carried. Baby strollers, automobiles and paid aid may shorten marriage duration. Orgasm releases dopamine in the pleasure center of the brain just as food and cocaine do. Its addictive nature is one reason why mates stay paired. Another reason is that females equate orgasm with a sensitive and caring mate. Collagen injections in the Gräfenberg Spot (G-spot) increase orgasm ease and intensity. Various chemical and electrical means will increase orgasm intensity and dopamine release in both males and females. As long as orgasm is equated with ones mate, it should result in stronger pair-bonding. Orgasm releases oxytocyn, particularly in females, which motivates the calm and comforting feelings and the need to cuttle. Humans who have decided to procreate may artificially increase oxytocyn levels to assure bonding with their mate as well as their progeny. Males with high levels of vasopressin tend to stay bonded longer. Humans who have decided to mate for life may artificially increase vasopressin levels Mutual excitement about new ideas and things tend to promote long-term bonding. Those who work together stay together.
Whether, strong, intelligent or stupid genes or subjective reality prevail remains to be seen.