Tenho a salientar um ponto deste texto da Psychology Today acerca de algumas investigações na área da psicologia evolutiva:
A beleza feminina como elevador social e o poder (status) masculino como sinónimo de sucesso reprodutivo. As pessoas bonitas costumam ter mais filhas do que filhos e as pessoas mais pobres tendem a ter mais filhas, pois os homens ricos, ao contrário das mulheres, casam-se com mulheres pobres (desde que atraentes).
"One of the most celebrated principles in evolutionary biology, the Trivers-Willard hypothesis, states that wealthy parents of high status have more sons, while poor parents of low status have more daughters. This is because children generally inherit the wealth and social status of their parents.
This hypothesis has been documented around the globe. American presidents, vice presidents, and cabinet secretaries have more sons than daughters. Poor Mukogodo herders in East Africa have more daughters than sons. Church parish records from the 17th and 18th centuries show that wealthy landowners in Leezen, Germany, had more sons than daughters, while farm laborers and tradesmen without property had more daughters than sons.
The generalized Trivers-Willard hypothesis goes beyond a family's wealth and status: If parents have any traits that they can pass on to their children and that are better for sons than for daughters, then they will have more boys. Conversely, if parents have any traits that they can pass on to their children and that are better for daughters, they will have more girls.
Physical attractiveness, while a universally positive quality, contributes even more to women's reproductive success than to men's. The generalized hypothesis would therefore predict that physically attractive parents should have more daughters than sons. Once again, this is the case. Americans who are rated "very attractive" have a 56 percent chance of having a daughter for their first child, compared with 48 percent for everyone else."
O resto do texto aborda mais 9 questões como o porquê de os casais que têm filhos homens se divorciarem menos ou o porquê de os bombistas suicidas serem quase sempre muçulmanos. Vale a pena ler e, naturalmente, questionar.