Now, a survey of both sexes has lifted the lid on whether member size does actually matter, as well as what people think is the "ideal" length.
Surprisingly, the survey found that people in the UK are pretty realistic about average and ideal penis length compared to other countries.
It also discovered that a lot of women think size is "somewhat important", but it's not a major cause for concern.
Oh, and one in five women don't care about penis size at all.
Dr Ed surveyed 2,121 respondents - 1,148 of which were male and 973 of which were female - on questions relating to sexual health and what they thought the ideal penis size was.
Survey results found that when it came to perceived average penis length and ideal penis length, people in the United Kingdom have fairly low expectations compared to other countries.
People in the UK believe the average penis is 12.4cm, while their ideal length would be 14.2cm.
The people of Poland had the highest expectations for both categories, suggesting that the average penis size was 15.7cm, while the ideal penis length was 17.3cm.
Austria, Italy and Germany also scored high for both categories.
Perceived average and ideal penis length also differed between genders.
Women believe the average penis length is 13.8cm, while their ideal penis length is 2cm greater at 15.8cm.
Meanwhile men think the average penis length is bigger at 14.1cm. They believe the ideal penis length to be 16.6cm.
"When considering notions of an ideal length, it becomes clear that expectations don't always match up with reality," reads the report.
"Women's perception of an ideal penis length was 2cm greater than the average length.
"While it's concerning that even an average penis size is seen as less than ideal, it's unclear whether a difference of only 2cm would have a meaningful effect on sexual satisfaction for a man or his partner."
They continued: "One of the aspects of men's size anxiety that looms the largest is concern over what partners might think and how important they consider size to be."
In order to estimate whether penis size does actually matter to women, Dr Ed asked females how much they valued penis size as an important aspect of a man's body.
Roughly two-thirds of women (67.4%) said that size is "somewhat important", but not of overriding significance or major concern to them.
A further 21.4%, more than one in five, said that penis size simply wasn't important.
While just 11.2% of women said that size was very important to them.
The report concludes: "Perceptions of penis size have become so distorted in the popular imagination that the reality is often ignored and exceeded by exaggerated notions of an ideal size.
"More than that, these beliefs vary substantially between nations and even states - what's considered 'ideal' in one place may not be so in another.
"Is it any wonder that men often struggle with anxiety about this very personal issue?"
It continues: "As we've found, most men continue to show satisfaction with their size, and most women don't consider size to be a crucial issue.
"At the end of the day, there's much more to satisfying relationships and sexual confidence than this one simple measure."