A Rutgers-led experimental study found that women prefer and invest more in daughters, while men favor and invest more in their sons.

The study of gender biases appears in the journal Scientific Reports.

"Our research may help people be better parents if we become aware of our unconscious biases towards different kinds of children," said senior author Lee Cronk, a professor in the Department of Anthropology at Rutgers University-New Brunswick.

Researchers conducted an online experiment to test the 1973 Trivers-Willard hypothesis, which predicted that wealthy parents would prefer and invest in sons, while poor parents would invest and favor daughters.

Participants completed a task that, based on previous research, fosters feelings of relative poverty or relative wealth. Then the researchers measured participants' preferences for daughters and sons in several ways. They included an opportunity to pledge money to a charity that largely supports girls or boys; a test that discretely measures participants' attitudes; gauging preferences for the sex of children they might adopt; and assessing the sex ratio they would prefer in their own offspring, according to Cronk, who works in the School of Arts and Sciences.

While the experiment yielded little support for the Trivers-Willard hypothesis, the participants' sex had a strong impact on what sexes they preferred for their offspring. Females strongly preferred daughters and investing in them, while males had a weaker though still significant preference for sons.

"These results may also have implications for rising income inequality and intergenerational social mobility," the study says. "A recent study using the tax records of 40 million Americans between 1996 and 2012 showed that the single best predictor of lower intergenerational social mobility was having a single or divorced parent. Because most of these single parents are females, and females prefer daughters, we might expect even lower reduced intergenerational mobility for the sons of these single mothers."

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The study's lead author is Robert Lynch, who earned a doctorate at Rutgers and is now at the University of Turku in Finland. Co-author Helen Wasielewski, who also earned a doctorate at Rutgers, is now at Arizona State University.