The retreat from sex is not an exclusively American phenomenon. Most countries don’t track their citizens’ sex lives closely, but those that try (all of them wealthy) are reporting their own sex delays and declines. One of the most respected sex studies in the world, Britain’s National Survey of Sexual Attitudes and Lifestyles, reported in 2001 that people ages 16 to 44 were having sex more than six times a month on average. By 2012, the rate had dropped to fewer than five times. Over roughly the same period, Australians in relationships went from having sex about 1.8 times a week to 1.4 times. Finland’s “Finsex” study found declines in intercourse frequency, along with rising rates of masturbation.
late 14c., "males or females collectively," from Latin sexus "a sex, state of being either male or female, gender," of uncertain origin. "Commonly taken with seco as division or 'half' of the race" [Tucker], which would connect it to secare "to divide or cut" (see section (n.)). Meaning "quality of being male or female" first recorded 1520s. Meaning "sexual intercourse" first attested 1929 (in writings of D.H. Lawrence); meaning "genitalia" is attested from 1938. Sex appeal attested by 1904.