A new study made by Indiana University sexuality researchers pinpointed 5.57 inches as the average size of the erect penis. The findings confirm previous studies on penis length. It had 1,661 American male respondents using the self-reporting technique.

For those who have no idea or are more familiar with centimetres, 5.57 inches would be just slight smaller than a U.S. $20 bill.

However, a discovery of the study is the link of oral sex with penis length. Dr Debby Hebernick, co-director of the Center for Sexual Health Promotion at the University's School of Public Health-Bloomington, disclosed that fellatio played a part in the respondents reporting greater length and circumference of their genitals.

However, Ms Hebernick said they are yet to establish if the results indicate that arousal during oral sex resulted in the penis becoming more erect or if a large erect penis attracts partners who are willing to perform fellatio on them.

Actually, the subject of the study was condoms, but "(We) later thought that others might be interested in the data, particularly because the men who have presumably been motivated to report their penis size accurately in order to receive condoms to fit their penis," Inquisitr quoted Ms Hebernick.

The accurate reporting of penis size served as an incentive for the men to receive condoms that fit their needs because if they pad results, they might get a baggier condom or if they are too modest, they could end up with up a tight contraceptive.

For men who want to know if their private parts are above or below average in size, all they have to do is use a ruler or tape measure for the length and a piece of string for the circumference. Or the prudish could instead use the Condom Size app.

The study was published online on July 10 in the Journal of Sexual Medicine.

Comments on the study posted in Daily Mail confirmed another study that many women prefer men with big penis. However, a German commenter suggested, "Isn't it time to make a study on the average size of the inside of a woman's vagina? Maybe that'll shut up some of those women who say size does matter."