How do people lose their virginity?

The general answer to this question is pretty simple: you lose your virginity the first time you have sex.

What complicates things is the fact that many people have a different idea of what counts as sex.

For many people, sex refers to penetrative vaginal sex (penis into vagina). 

Therefore, a virgin is a man or a woman who hasn’t yet engaged in this kind of sex—and having this kind of sex is how a person loses his or her virginity.

For others, penetrative anal sex (penis into anus) also counts as sex. Therefore, people lose their virginity the first time they engage in vaginal or anal sex.

Then there are those who believe that oral sex also counts as sex.

Lastly, some people believe that every sexual act that involves stimulation of the genitals—including mutual masturbation and dry humping—counts as sex.

Again, it all depends on what you consider to be sex. Whatever that is, the first time you do it, you are no longer a virgin.