from my scientific collection of soft and hard pornography
1   10  20  30  40
2   11  21  31  41
3   12  22  32  42
4   13  23  33  43
5   14  24  34  44
6   15  25  35  45
7   16  26  36  46
8   17  27  37  47
9   18  28  38  48
A random sample of Canadian and U.S. sex therapists
said that sexual intercourse of seven to 13 minutes is
most "desirable."

       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 Journal of
Sexual Medicine.