| 1 | Can evolution account for female masturbation in the animal kingdom? | |
| 2 | If you have a partner, do they know when you' ve masturbated? | |
| 3 | And, of course, masturbation is the greatest expression of self-love. | |
| 4 | That idea was first proposed to explain human masturbation in 1965. | |
| 5 | In both these studies, ejaculation frequency included sexual intercourse and masturbation. |