Men with small testicles care more to their children - CNN

Washington. (EFE). – The men with testicles more small are more likely to engage in the daily care of their children , according to an Emory University study published today in the Proceedings of the National Academy of Sciences.

smaller testicular volumes are also associated with more brain activity related to aging parents when they see pictures of their own children, the study added.

“Our data indicate that male human biology reflects a compromise between what is most important for mating and it leans more towards the upbringing,” said Emory anthropologist James Rilling, who led the research.

The study set out to determine why some parents invest more time, effort and attention than others in parenting.

“It’s an important issue because other studies have shown that children whose parents are more involved in parenting have improved social, psychological and educational,” said Rilling.

evolutionary theory holds that the evolution life improves resource allocation, either to the mating or breeding range so that fitness maxima.

While there may be social, economic and cultural factors that affect the degree of attention given to the foster parents, the researchers looked for biological factors.

are known to lower testosterone levels are correlated with greater involvement in parenting, and that higher levels of this hormone predict more divorce and polygamy.

addition to the production of testosterone, the testes produce sperm and testes size is more related to the quantity and quality of sperm that hormone levels.

Researchers interviewed

seventy men who were biological parents of sons and daughters aged one and two years, and living with the child and his biological mother.

Scientists interviewed separately to mothers and parents to determine the degree of involvement of men in the care of children in tasks like changing diapers, feeding, bathing, or stay home to care for them when are sick.

men were measured your testosterone level and by functional magnetic resonance image (MRI) was measured brain activity when watching pictures of their children with expressions of happiness, sadness and neutral.

Using structural MRI volume was measured from the testes of the participants.

The findings showed that both testosterone levels as the size of the testicles are inversely related to the degree of direct paternal care which had realized men and women in the interviews.

The article notes that while testosterone levels may be more related to competition between males prior to mating, testicular volume may reflect a postcopulatoria mating investment.

addition, the authors noted that in the last fifty years the number of women who are raising children on their own has grown substantially in the United States and that although there are many more households with no parent present, in those in which the parent is present it tends to be much more involved in parenting than parents of the past.