since pregnancy cannot happen if sperm are kept out of the vagina, outercourse is one method of birth control.
Examples of outercourse
outercourse
Outercourse is sex without penetration.
From the time.com
So I wouldn't expect the exclusive outercourse option to become widely preferred any time soon, unless genes really do have nothing to do with behavior.
From the guardian.co.uk
More examples
Sexual stimulation without vaginal penetration; "since pregnancy cannot happen if sperm are kept out of the vagina, outercourse is one method of birth control"
Non-penetrative sex (also known as heavy petting, outercourse, petting, dry sex, and dry humping) is sexual activity without vaginal, anal, or oral penetration, as opposed to penetrative aspects of intercourse, anal sex, or oral sex. ...