Call the cops and scream for help
Answer
abstinence
Explanation
sexual intercourse can be safe if practiced properly, using a condom can prevent stds. sexual intercouse without protection runs the risk for sexually transmitted diseases and other related health problems. abstinence is the only way to assure that you will not contract any of the above.
Their research was about the nature of human sexual response and the diagnosis and treatment of sexual disorders and dysfunctions. (Research started in 1957and ended in the 1990’s)
If you round it up you will get 20.