Number of Sexual Partners and Relationship Status Are Associated With Unprotected Sex Across Emerging Adulthood

Sex with multiple partners, consecutively or concurrently, is a risk factor for contracting sexually transmitted infections (STIs) as multiple partner–partner contacts present increased opportunity for transmission. It is unclear, however, if individuals who tend to have more partners also use protection less reliably than those with sexual histories of fewer partners. Longitudinal data can elucidate whether an individual shows a consistent...