According to a study, girls who participate in girls-only activities are far less likely to experience a teenage pregnancy and less likely to be sexually active in general. Participating in competitive sports has also shown to have an effect for girls. A study published in 1999 found that female adolescents who participated in sports were less likely than their non-athletic peers to engage in sexual activity and/or report a pregnancy. Males interested in arts are also less likely to be involved in a pregnancy situation. It is unclear whether these correlations are causal or the reflection of the underlying bias of the considered population. The study that reported these findings did not take into account the sexual orientation of the subjects.