Half-Siblings More Likely to Start Unhealthy Habits in Life Early

A recent study suggests that half-siblings with a different father may be more likely to turn to unhealthy habits early in life.

In fact, according to researchers at Bowling Green State University, by age 15, many may have done drugs or already had a sexual partner.

However, researchers  are not a bit surprised by their findings.

"It's not new behavior, but it's happening more often as more people are having children outside of marriage," said one of the study authors, Karen Benjamin Guzzo, an assistant professor of sociology at Bowling Green State University, via a press release.

Researchers looked at data from the National Longitudinal Study of Youth and examined a phenomenon known as "multi-partnered fertility" or MPF. This can happen when parents who are not romantically involved with each other from new relationships have another child with a new partner.

Researchers looked at connections between re-partnering and additional childbearing on adolescent drug use and early sex, keeping a particular focus on mothers and first-born children who lived with their mother most of their lives.

"For children, MPF means having a half-sibling, but it also means, for first-born children, that they usually experienced their biological parents splitting up - if they were together at all, lived in a single mother household for some time, experienced their mother finding a new partner at least once and perhaps lived with a stepfather, and finally experienced their mother having a baby with a new partner," Guzzo explained, via the release.

They also looked at the mother's educational background, family structure growing up and whether or not the child had experienced bouts of poverty.

"We find that first-born adolescents with half-siblings with the same mother but a different father do have less favorable outcomes compared to their peers with only full siblings, even after accounting for the mother's background characteristics, socioeconomic factors the child experienced growing up, and family instability and structure," Guzzo said.

"Adolescents with a half-sibling with a different father are about 65 percent more likely to have used marijuana, uppers, inhalants, cocaine, crack, hallucinogens, sedatives, or other drugs by the time of their 15th birthday than those who have only full siblings. They are also about 2.5 times more likely to have had sex by their 15th birthday than their peers with only full siblings."

However, she adds that they're uncertain at this time what exactly drives the outcome and further studies will be needed in order to determine the exact link.

More information regarding the study can be found through the American Sociological Association.