9 Bizarre Ways Your Siblings Affect You as a Grown-Up

Updated: Feb. 15, 2018

Your brothers and sisters can influence everything from your weight to your risk of divorce.


Having many siblings lowers your divorce risk

If you come from a big family, you may be less likely to get divorced. Ohio State University researchers analyzed data from 57,000 Americans over a 40-year period and found that those with siblings are more likely to stay married than only children. Each sibling decreases a person’s divorce risk by about 2 percent. (There are diminishing returns: After about seven siblings, there’s not much additional payoff.) Bigger families may allow more opportunities to practice good communication, empathy, and negotiation, skills that may fortify marriage. Learn more about why your siblings are some of the most important people in your life.

iStock/Bogdan Kosanovic

Being mom’s favorite could impact depression

Were you the golden child? It may not make you happy. Purdue University and Iowa State University researchers found that depressive symptoms were most common in adult children who claimed to be closer to their mothers than their siblings were. Sibling rivalry may play a role (a mother’s attention may not nullify negative attention from jealous siblings), or favorites may be likelier to care for an aging mother, which can take an emotional toll. Why do adult siblings stop speaking? Take a look at the psychology behind sibling estrangement.


An opposite-sex sibling could boost your dating skills

Growing up with a sibling of the opposite sex could increase an individual’s confidence in romance. Pennsylvania State University researchers analyzed five years of yearly interviews with nearly 400 children. Participants (ages 12 to 20) were asked about their perceived romantic competence, such as if they would be fun on a date or if others would find them attractive. At age 12, perceived romantic competence was significantly higher among same-sex siblings. But by age 20, opposite-sex siblings perceived themselves significantly more skilled than the same-sex siblings. The findings suggest opposite-sex siblings have natural opportunities to practice relating to the opposite sex, and may better realize the challenges in doing so (while same-sex siblings may not be aware of how little they know).


Heavy siblings raise your risk of being obese

Your siblings have more pull than any other family members when it comes to your weight. One study published in the American Journal of Preventive Medicine found that having an obese older sibling could make a child up to five times more likely to become obese themselves, regardless of their parents’ weight. Gender also comes into play. For same-sex siblings, a younger boy with an obese older brother is 11.4 times more likely to be obese and a younger girl with an obese older sister is 8.6 times more likely to be obese. A younger boy with an obese older sister was 6.6 times more likely to be obese. Meanwhile, a girl with an obese older brother was not significantly more likely to be obese. Learn more about how your birth order affects your health.


Having a brother can increase a sister’s caregiving burden

Responsible sisters, beware: you’ll likely provide more care to your aging parents than your male siblings. One Princeton University study found that daughters tend to bear the brunt of caregiving duties for elderly parents, and that sons may pass on these responsibilities to their sisters. The research suggests that because women are often raised to be caregivers, an older woman might feel less comfortable with her son taking care of her than her daughter. No matter the reason for your family’s distribution of responsibilities, have a group discussion to make sure no one feels overwhelmed or taken advantage of. Here’s how to strengthen your relationship with your siblings as an adult.

iStock/Craig Dingle

Sibling bullies can leave lasting effects

While the occasional sibling scuffle is inevitable, constant teasing can create lasting hurt. One study found that kids who were bullied—which the researchers defined as being subjected to name-calling and being made fun of, as well as physical violence, like being hit or kicked—were more than twice as likely to report depression or self-harm at age 18 than those who weren’t bullied by siblings. They were also nearly twice as likely to report anxiety. The researchers believe that intervening in sibling bullying would likely improve children’s mental health in the long run. If you yourself are a parent of more than one child, use these tricks to stop sibling rivalry before it starts.


A sibling’s death dramatically raises your risk of heart problems

Recent research found that when a sibling dies, especially if it’s from a heart attack, the surviving sibling’s risk of also dying from a heart attack increases sharply in the following years. Although the reasons for this association aren’t clear, the researchers noted it could be because of chronic stress or habits like drinking, smoking, unhealthy diet, and lack of exercise that a sibling might adopt during the grieving process.


A sibling with VTE? Watch your own risk

One Swedish study found that people who have two or more siblings who have suffered from blood clots in deep veins, a disease know as venous thromboembolism (VTE), have a relative risk 50 times higher for developing such clots themselves. Risk for VTE is higher in men than in women, and other risk factors include surgery, heart failure, smoking, obesity, cancer, long periods of inactivity, sitting or lying in bed, fractures in the legs or hip, and taking birth control pills. If you have a family history of VTE, let your doctor know before any surgery. That will allow him or her to take preventative measures to prevent the risk of clotting. These healthy habits can help prevent deadly blood clots.


No siblings? Don’t worry: You’re not destined to be a brat

If all this sibling talk has got you nervous, take comfort in knowing that recent studies have found that children without siblings are no less capable of connecting with their peers than those raised with siblings. One Ohio State University study tested high school students’ popularity by asking them to list up to five male and five female friends, and then tallied the overall number of votes each participant got. Students were “nominated” an average of five times, and their scores were not influenced by the presence of siblings. “Kids interact in school, they’re participating in extracurricular activities, and they’re socializing in and out of school,” study co-author Donna Bobbit-Zeher said in a news release. “Anyone who didn’t have that peer interaction at home with siblings gets a lot of opportunities to develop social skills as they go through school.” Learn more about what your birth order (including being an only child) says about you.