Having Friends Of The Opposite Sex May Lower High School Students' Grades

SAN FRANCISCO (CBS SF) -- The debate over single-sex versus mixed gender education just got more interesting. A new study reveals that mixing with the opposite sex may actually have a negative affect on high school students' grades.

A researcher at the University of South Carolina found a correlation between having friends of the opposite gender and high school performance. The more friends of the opposite sex the students in the study had, the lower their grades were.

The study entitled, "The Girl Next Door: The Effect of Opposite Gender Friends on High School Achievement," was published in the American Economic Journal: Applied Economics.

Researcher Andrew Hill looked at friendships among high school boys and girls who went to each other's houses, hung out after school, shared their problems, spent time together on weekends, and talked on the phone.

Hill found that for every 10% more of the opposite sex among a student's friends, his or her grade-point average declines by one-tenth.

One-tenth may seem minute, but here is some perspective. On a grade-point scale of 0-4, one-tenth can be the difference between a 2.9 and a 3.0 GPA -- the minimum requirement for admission to the University of California (most students far exceed the minimum).

Mixed friendships also have a negative impact on classroom behavior, according to the study. Students with more opposite gender friends had more difficulty getting along with teachers, and paying attention in class. They were also more likely to develop romantic relationships, which could reduce the quality and quantity of time spent on homework, leading to lower student achievement. Furthermore, mixed-gender friendships seemed to adversely affect girls three times more than boys.

Research also showed the overall effect was greater in math and science for students 16 and under. For older students, the effect was "equally prevalent across all school subjects.

One interesting note: The author of the study found no correlation between a student's share of opposite gender friends and "detrimental cool behavior" like smoking, drinking and other risky behaviors outside the classroom.

Hill concludes that educators should reorganize classroom gender composition particularly for math and science courses to optimize student achievement. He says it is "a relatively low-cost policy as it need not require more teachers or resources."

CBSSF.com writer, producer Jan Mabry is also executive producer and host of The Bronze Report. She lives in Northern California. Follow her on Twitter @janmabr.