Conception is a natural process. When a girl and boy are conceived at a time, the female twin may have a boyish behavior. She is exposed to more male hormones in the womb than when both babies are girls. New research reveals women who have a twin brother are less likely to complete their studies. She tends to earn less as time passes. To know the fact, the researchers decided to test the talked-about impact of male hormones before birth. As a result, they discovered those hormones have a little negative effect on life achievements. The effect of being nine months closer to a boy plays an important role and is statistically relevant.
Researchers in Norway and at the Northwestern University assert that exposure of male testosterone in the womb may damage the girl twin. It also results in the worst mental functioning and fertility. A 30-year study found among girl-boy twins; the girl performs less in academics and social life. Whereas, the girl-girl twins, both perform best. As per researchers, the number of twins birth per annum increased due to IVF technology. They found an impact on the number of children and successful marriage rates, after studying data concerning thousands of twins born in Norway.
The team revealed that the effects were due to the twin testosterone-transfer theory. In the hypothesis, hormones transferred to female twin from her brother has a remarkable impact on their actions and behavior. Girls often get a feature of more aggressiveness from their twin brother. But researchers say it could take place while growing up with a brother. Compared to other twins, the girls who developed alongside a boy in the womb faced various disadvantages in their life. These female twins experienced about 6% lower fertility rates and were almost 12% less probably to marry. But the exposure to more estrogen in the womb did not appear to affect the boy twins. Although, the researchers note the probability to get this type of twins will rise if the rate of IVF will increases.