Is Penis Size in The Eye of the Beholder?

Is Penis Size in The Eye of the Beholder?

Transgender individuals, whose gender identity differs from the sex they were assigned at birth, may seek gender-affirming surgeries (GAS) to alleviate gender dysphoria. These surgeries aim to create genitalia that match their gender identity. For example, transgender men may desire phalloplasty, a surgery to create a penis.

However, individuals may find that communicating desired penis size accurately during preoperative discussions is a challenge. Therefore, a new study explored how accurately people can visually estimate penis size. Many misconceptions about penile size exist, impacting transgender patients’ expectations and surgical outcomes. Understanding these perceptions can improve preoperative counseling and surgical planning for transgender individuals seeking phalloplasty.

Researchers collected data from 25 transgender men (TM), 47 transgender women (TW), 30 cisgender men (CM), and 40 cisgender women (CW) between January and August 2020. Participants viewed six penis models, called packers, commonly used by TM. Each model varied in length, width, and girth.

The models were randomly presented, and participants could not touch them. Instead, they were asked to estimate the dimensions visually. A bright green suture marked the measurements’ focus points so that each of the participants would be visually assessing the same areas.

Once the data was collected, the researchers compared the participants’ estimations to actual measurements, analyzing bias among gender groups with statistical tests. The findings aimed to understand how accurately individuals perceive penis size to aid transgender patients in surgery discussions.

All 142 participants involved in the study estimated the dimensions of six penis models. Ultimately, the results showed variations in estimation accuracy among groups. CM mostly overestimated the length of the penile models, while CW and TM did so less. When it came to penile width, all groups overestimated. CW and TW underestimated girth, while TM did not. Variations existed in individual estimates across all models and groups, suggesting diverse perceptions of penis size.

The results of this study highlight the significant variability and inaccuracy in visually estimating penis size among different groups. All of the participants tended to overestimate penile length and width while underestimating penile girth.

CM were generally the least accurate, overestimating average-size models and often seeking penis enlargement treatments. TW’s overestimation of a partner’s penis length may lead to unnecessary surgical risks for vaginoplasty, while TM’s overestimation could result in a larger-than-desired phalloplasty.

Realistic penis models could help align individuals’ expectations with actual sizes for better preoperative counseling and surgical decisions. These findings are very important for improving patient satisfaction and safety in gender-affirming surgeries.

For more information on this topic, please read these publications from the ISSM Journals: The Journal of Sexual Medicine, Sexual Medicine Reviews, and Sexual Medicine Open Access:

Beliefs about Penis Size: Validation of a Scale for Men Ashamed about Their Penis Size

Systematic Review of Surgical and Nonsurgical Interventions in Normal Men Complaining of Small Penis Size 


Castaneda, P. R., Zaliznyak, M., Sandhu, S. S., Cook-Wiens, G., Smith, S. M., Mallavarapu, S., & Garcia, M. M. (2024). Is size in the eye of the beholder? Visual estimation of penis size among transgender and cisgender people and implications for genital gender-affirming surgery and sexual medicine. The Journal of Sexual Medicine, 21(2), 175–180.