The survey of North American sex therapists found they thought an "adequate" length for sexual intercourse was from three to seven minutes; "desirable" from seven to 13 minutes; "too short" from one to two minutes; and "too long" from 10 to 30 minutes.

Researchers Eric W. Corty and Jenay M. Guardiani of Penn State Erie, The Behrend College, said that lay public perceptions about how long sexual intercourse should last may be problematic and may be a factor related to perceived distress.

Dissemination to the public of these results may change lay expectations and prevent distress and may benefit couples in treatment for sexual problems by normalizing expectations, the researchers said.

The findings are published in the The Journal of Sexual Medicine.