New York, Oct 17 (IANS): For those who join college, the odds of unprotected sex in hook-ups get doubled between freshers and the final year students, says a study.

Freshmen or freshers from less advantaged socio-economic backgrounds more frequently protect themselves with a condom when they have intercourse in a hook-up than freshmen from more advantaged backgrounds.

"However, by the final year, they adopt the same lower condom use rate of their peers from more advantaged backgrounds," said Jonathan Marc Bearak, doctoral candidate in sociology from New York University.

The study explored the changes in undergraduate uncommitted sexual behaviour during college years.

The research provided reasoning for the decline in the use of condoms, and explains how changes in the odds of coitus and condom use depend on family background, school gender imbalance and whether the partners attend the same college.

"It may take longer for students from poor backgrounds to integrate into the social activities on their campus, which, conceivably, may not encourage condom use," Bearak suggested.

This research also highlights the probability of intercourse within the normative contexts in which adolescents and young adults sexually interact that contributes to cumulative risks over and above their contraceptive practices.