Alters S (2012). Essential Concepts for Healthy Living. Jones & Bartlett Publishers. стр. 180—181. ISBN978-1449630621. „Most heterosexuals are familiar with the notion of 'having sex' or sexual intercourse as vaginal sex, the insertion of a penis into a vagina. Vaginal sex, or coitus, is the most common and popular form of intimate sexual activity between partners.”
Sexual intercourse most commonly means penile–vaginal penetration for sexual pleasure and/or sexual reproduction; dictionary sources state that it especially means this, and scholarly sources over the years agree. See, for example;
Chughtai, Bilal; et al. (2005). „A neglected gland: a review of Cowper's gland”. International Journal of Andrology. European Academy of Andrology. 28 (2): 74—77. doi:10.1111/j.1365-2605.2005.00499.x.