In fact, 40 percent of adults aged 65-80 are sexually active and about 10 percent of people older than 90 are sexually active, though it bears noting that the latter figure is based on a survey limited to one municipality in Sweden.

But STDs spare no one. Few people I’ve seen whose STD testing comes back positive were expecting that result. And from 2007 to 2017, STD cases more than doubled among adults age 65 and over.

That is why it is important to get screened and always use a condom. Condoms are infrequently utilized among older people, but they do reduce, yet not eliminate, risk of STDs.

Researchers speculate STD cases are rising simply because older adults are having more sex than in generations past.

One factor at play is how people are meeting each other and forming relationships, including with web- or app-based dating services that are increasingly attracting older people.

The market for devices and medications that address sexual health problems is also flourishing — and not just for men. In the past several years, the Food and Drug Administration has approved more treatments aimed at postmenopausal women who may have trouble with sex due to vaginal dryness and pain.

This all may be impacting how often older adults have sex and subsequently get STDs. After the introduction of sildenafil — known by the brand name Viagra — in 1998, for example, the risk of STDs increased significantly among widowed men.

The United States Preventive Services Task Force advises all women aged 24 and younger to get screened for gonorrhea and chlamydia regularly — and thereafter, when you have new sexual partners or other situations that increase risk. Everyone should be tested for HIV at least once. The Centers for Disease Control and Prevention recommends men who have sex with men to get screened at least once a year for syphilis, chlamydia, gonorrhea and HIV.

But there’s a lot of leeway among other groups, so much of STD screening is left to common sense.

Here’s my advice:

In other words, if you’re even thinking about getting screened, just do it.

Chlamydia and gonorrhea are two classic STDs that have been rising among older adults in recent years. There were more than 2,000 cases of each among people 65 and older in 2017. Syphilis, while rarer, is also rising in this population, and in 2018, the majority of people diagnosed with HIV were age 50 and older.

There are also other conditions that get less attention, such as trichomoniasis and bacterial vaginosis (the latter is not quite considered an STD but is linked to sexual activity). Both can produce a distinctive “fishy” smelling discharge in women. Discuss which STDs to check for with your health-care provider since your personal history plays a role as well.

Sure, painful genital sores raise a red flag pretty quickly, but most people with STDs don’t actually have any symptoms. If you have symptoms like burning with urination, itching or unusual discharge, consider the possibility of an STD with your provider before immediately presuming it’s a urinary tract or yeast infection.

Also keep the following in mind:

To be clear, cases of STDs among the elderly are going up, but they’re still much fewer than those among older teenagers and adults in their 20s. But everyone, regardless of age, should take precautions and test appropriately.

Age aside, men who have sex with men, users of intravenous drugs and people who have a prior history of another STD are all at higher risk. A study from Vanderbilt University, where I went to medical school, recently found what I had long observed as a student: Compared to other groups, Black women are losing the most years of life to HIV (and 91 percent of new HIV infections among Black women nationwide are reported from heterosexual contact).

There’s another striking discrepancy within the country: Southern states account for about half of new HIV cases annually. These states, not coincidentally, also have the highest rates of poverty nationally and tend to focus on abstinence-based sex education that has been shown to be ineffective in STD prevention.

I never enjoy telling someone they have something like chlamydia. But I do like what I can say next, which is that most STDs can be fully cured with medication, and for those we can’t cure, like HIV, we have excellent medications to treat. You only stand to win by knowing.