Female female 103 Humans 100 human 100 male 89 Male 86 adult 61 psychology 58 Adult 53 adolescent 43 Adolescent 42 Young Adult 29 child 29 young adult 29 Middle Aged 27 article 27 middle aged 27 Child 26 major clinical study 26 Article 23 HIV Infections 23 Human immunodeficiency virus infection 23 controlled study 20 physiology 20 statistics and numerical data 19 United States 16 Child, Preschool 15 preschool child 15 Sexual Behavior 14 complication 14