A scientific study has found that women tend to find men with larger penis size more attractive, challenging the long-standing belief that size does not matter.
The research, published in the peer-reviewed journal PLOS Biology, explored how physical traits such as height, body shape and genital size influence sexual attraction and perception.
The study was led by Dr Upama Aich of the University of Western Australia, who said the findings confirmed earlier evidence that penis size plays a role in how women judge male attractiveness.
“We confirmed our earlier finding that women find a larger penis more attractive,” Aich said.
The researchers set out to understand why the human penis is proportionally larger than that of other great apes, despite its primary biological role being reproduction.
To investigate this, they conducted an experiment involving more than 600 male and 200 female participants.
Participants were shown computer-generated male figures that varied in height, body shape and penis size. Women were asked to rate the figures based on sexual attractiveness, while men assessed how threatening the figures appeared, both physically and sexually.
The results showed a clear pattern.
Women generally rated men who were taller, had a V-shaped upper body and larger penis size as more attractive. However, the study also found that beyond a certain point, increases in size or height had little additional effect on attractiveness.
For male participants, penis size carried a different meaning.
The study found that men viewed larger penis size as a signal of a stronger rival, both in terms of physical dominance and sexual competition.
Researchers said this suggests that penis size may have evolved for two key reasons.
First, to attract potential partners. Second, to signal strength and competitiveness to other males, similar to traits such as antlers in deer or manes in lions.
According to the study, sexual preference appears to play the stronger role.
It found that the effect of penis size on attractiveness was “four to seven times higher” than its role as a signal of fighting ability.
Co-author Michael D Jennions, a Professor Emeritus of Evolutionary Biology at the Australian National University, said the findings point to a broader explanation for human physical traits.
“While the human penis functions primarily to transfer sperm, our result suggests its unusually large size evolved as a sexual ornament to attract females rather than purely as a badge of status to scare males, although it does both,” he said.
The researchers also noted that early humans lived without clothing, meaning physical traits would have been visible and could influence both attraction and competition.
However, the study acknowledged some limitations.
It did not account for other factors such as personality, facial features or emotional connection, all of which can shape attraction in real life.
The authors also pointed out that standards of masculinity and attractiveness vary across cultures and can change over time.
Overall, the study suggests that attraction is not fixed, but shaped by a mix of biological signals, social context and individual perception.
