Studies show a relationship between mothers’ income levels and children’s finger lengths

Low-income mothers conceive their unborn babies by altering their hormones, but high-income mothers fertilize their children, a large finger-based study found , led by a Swansea University expert.

Surprise is an unconscious evolutionary response aimed at increasing the chances of their children successfully reproducing.

It helps, in part, explain links between low income, low levels of prenatal testosterone, and major causes of mortality such as cardiovascular disease.

The study was based on the relationship between a person’s index length and ring fingers, known as the 2D: 4D ratio. A longer ring finger is a sign of higher testosterone levels, but a longer index finger is a sign of higher estrogen levels. In general, men have longer fingers, but women have longer fingers.

The 2D: 4D ratio is a widely debated measure that has been the subject of over 1000 studies, but what is important about the new report is that the team examined the ratio. assessment of parental income.

Led by Professor John Manning of Swansea University, with colleagues in Austria and Jamaica, the team tested hypotheses about the effects of evolution on the mother and her children. This suggests that, for higher-income mothers, sons have higher reproductive success compared to girls. For lower-income mothers, by contrast, girls will be more productively successful. Known as the Trivers-Willard hypothesis, its lead author, Professor Robert Trivers, was also involved in this new study.

The team used data from more than 250,000 people from around 200 countries, who took part in an online BBC survey. Participants were asked to measure their index and fingers and instructed on how to do this correctly. They were also asked to indicate their parents’ level of income.

The results showed:

• Children of higher-than-average income parents had a lower 2D: 4D ratio, with longer ring fingers, showing high testosterone and low estrogen before birth, more masculine fetus symptoms
• On the other hand, children of parents with lower incomes had a higher 2D: 4D ratio than longer index fingers, which show lower testosterone and higher estrogen before birth, signs of fetus more female
• These effects were present for both men and women

Professor John Manning from Swansea University’s A-STEM research team in sports science, lead researcher on the study, said:

“Our findings show that high-income mothers can reduce high levels of testosterone compared to estrogen early in pregnancy, thus justifying their male and female offspring. that is, low-income women can secrete low levels of testosterone, which both females and females give birth to.

This is an evolutionary response, on which mothers will not be aware, let alone gain control. It aims to give children the best chance of reproductive success.

For high-income mothers, the high testosterone benefits for their sons tend to outweigh the disadvantages for their daughters. For low-income mothers, the fitness gain from female daughters tends to outweigh the fitness loss for female sons.

This pattern is consistent with the Trivers-Willard concept. “

Dr Manning explained how the findings could shed light on disease vulnerability:

“These trends suggest significant public health effects of poverty.

Low testosterone and high estrogen in the male fetus of these men, as adults, could lead to poverty-related diseases such as heart attacks, strokes, and high blood pressure.

Poverty is known to be closely linked to worse health. What our research shows is that this connection can be reproduced over generations ”.