The US Centre for Disease Control and Prevention reports that chlamydia infections have increased by 31% and syphilis by 52% for Americans aged 65+ between 2007 and 2011. They specifically point to Viagra and free living in retirement communities as major contributors.
The National Survey of Sexual Health and Behaviour reports that for people aged 60+, more than 50% of the men and 40% of the women are sexually active. STD tests now match the popularity of colonoscopies for Americans over 65 who receive government healthcare. According to an Annals of Internal Medicine study, older men using Viagra were six times less likely to use condoms than men in their 20s. Pregnancy may be less of a concern.