by Growing up as the oldest sister, author YL Wolfe often felt that the lines between her role and that of her mother were blurred.
“By the time my youngest brother was born when I was almost 11, I was overwhelmed with feelings of responsibility for his welfare. I used to sit next to his crib watching him sleep to make sure he was safe,” Wolfe, the oldest of four, told HuffPost.
“It’s not that I thought my mother wasn’t competent – it was more that I felt we were both responsible for the family at that point in my life,” she explained. “As if I was ‘another mom’ rather than a big sister.”
In other words, Wolfe is very familiar with “eldest daughter syndrome.” The internet is full of musings about the plight of older daughters and tweets about how we could – perhaps I’ll reveal my bias here – unite: “If you’re the oldest sibling and a girl too maybe you would be entitled to financial compensation,” one woman made fun of X, the platform formerly known as Twitter.
Although “eldest daughter syndrome” is a pop-psychology term—you won’t be listed as an official diagnosis in the DSM-V—a new study suggests there may be more science to the pseudo-syndrome than previously thought. .
A research team led by the University of California, Los Angeles found that, in some cases, first-born daughters tend to mature earlier, enabling them to help their mother raise younger siblings.
Specifically, the researchers found a correlation between early signs of adrenal puberty in first-born daughters and their mothers following high levels of prenatal stress. (They did not find the same correlation in daughters who were not born first).
Why is the age of adrenal puberty important? Changes to skin (acne, for example) and body hair occur during this stage, but so do changes in brain development. Adrenal puberty processes are believed to induce social and cognitive changes; basically, there is a correlation between superficial physical changes and emotional maturity.
When times are hard and mothers are stressed during pregnancy, it is in the mother’s adaptive interest that her daughter matures socially at a faster pace, said Jennifer Hahn-Holbrook, one of the study’s co-authors and assistant professor of psychology. at the University of California, Merced.
“It gives mom a ‘helper-at-the-nest’ earlier, helping the females keep the last offspring alive in difficult environments,” she said.
Notably, adrenal puberty does not include breast development or the onset of menstruation for girls (or testicular enlargement, for boys). The study suggests that girls become mentally mature enough to care for their younger siblings but are physically unable to have children of their own, which would naturally pull them away from the responsibilities of their older daughters.
The older brothers seem to be immune to this type of parenting: The researchers did not find the same result in boys or daughters who were not the firstborn.
“One reason we did not find this effect for first-born boys is that male children help with childcare just as often as female children, so mothers have less adaptive incentive to delay their pubertal social development. speed up,” explained Hahn-Holbrook.
In addition, she said, previous research suggests that women’s timing of puberty is more malleable in response to early life experiences than men’s.
The results of this study, published in the February issue of Psychoneuroendocrinology (say five times fast – or just once), have been a long time coming: Researchers tracked the families for 15 years, from the stage of pregnancy to the children’s teenage years.
Researchers recruited women from two obstetric clinics in Southern California during routine prenatal care visits in the first trimester. On average, the women were 30 years old and pregnant with one child, not twins.
This was their first pregnancy for about half of the participants. The women did not smoke and did not use steroid medications, tobacco, alcohol or other recreational drugs during pregnancy. They were all over 18 years of age.
At five different stages of pregnancy, the women’s levels of stress, depression and anxiety were measured, and then measured cumulatively. The depression assessment asked the women to rate the truth of statements such as “I felt lonely”, and the anxiety question asked how often they felt particular symptoms, for example “jittery”.
Of the children born to these mothers, 48% were female and 52% were male.
As the children got older, characteristics of adrenal and gonadal puberty were measured separately – things like body hair, skin changes, height growth or growth spurts, breast development and onset of menstruation in women and voice changes and facial hair growth in males.
The study also assessed childhood adversity to account for other factors associated with precocious puberty or signs of puberty in children, such as parental death or divorce before age 5 and fatherlessness and economic uncertainties at ages 7-9 .
Taking all that into account, the older girls matured the fastest when their moms had high levels of prenatal stress.
Other studies suggest that there are some payoffs later in life for older girls who are responsible: A 2014 study found that older daughters are the most likely to outgrow any type of siblings, and a study found in 2012 they were the oldest born. they are more likely to have leadership roles.
The results ring true for Wolfe, the aforementioned author who said she felt like a second mother to her siblings growing up.
“I’m not surprised by what the study found,” Wolfe said. “My story is a little different – I went through real puberty, not just adrenal puberty, at 12, although I suspect I experienced early cognitive maturation.”
The study is also interesting for another reason: The results contribute to social scientists’ growing understanding of fetal programming, an interesting area of study that investigates the impact of stress and other emotional and environmental factors during pregnancy on a woman’s their children long after birth.
“This is a first-of-its-kind finding and it’s fascinating to look at it through an evolutionary lens,” Molly Fox, a UCLA anthropologist and one of the study’s co-authors, said in a press release.
In an interview with HuffPost, Fox delved deeper into how fetal programming works.
“One interesting theory is that when you’re still a fetus in your mother’s womb, you get clues about what life will be like, and your body can flexibly adjust the shape of your life cycle to suit it. those conditions you would expect,” she said.
Fox and his co-authors are excited to have their work out there for the public to read, especially after following the families for so long. The fact that the results were published just as a cultural conversation about older daughters began was just icing on the cake, especially for Fox, the oldest daughter. (She is a twin.)
“As the oldest, I think it’s a special role in any family because of the possibility of being close to my mother and the ability to take care of my younger siblings,” she said.
Talk like a true eldest daughter.
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