A Study Of Nearly 730,000 Births, Btw 1967-1978, Including 13,800 Twins, From Norway, Is Indicating That Females In Female-Male Twins Are Less Likely To Achieve Social Economic Success Than Females In Female-Female Twins. And This May Be Linked To Prenatal Testosterone In Female-Male Twins. But The Mechanism Is Still Uncertain.
Girls who share a womb with boys tend to make less money than those with twin sisters | Science | AAAS
Provocative study looked at more than 700,000 births over more than a decade