Women who've witnessed or been the victims of violence may be more likely to engage in risky sexual behaviour.
Heart attack survivors are more likely to resume their sex lives if doctors reassure them it's safe.
Having a partner who shows controlling behaviour raises the risk of suffering physical and sexual relationship violence.
Having sex early in a relationship may lead to less satisfying marriages because couples can fail to develop important skills to communicate well and resolve conflicts.
People who "hook up" for casual sex can have as rewarding a long-term relationship as those who take it slowly and establish a meaningful connection before they have sex.
Heterosexual adults who engage in partner swapping or attend sex clubs for couples - have rates of sexually transmitted diseases comparable to teenagers and gay or bisexual men.
Better health translates into better sex lives, with healthy people more likely to engage in sex and to express an interest in sex.
Badly-fitted condoms not only reduce the pleasure of sex for men and women, but also raise the risks of sexually transmitted infections (STI) and pregnancy.