Pedophilia may develop in the womb, according to the authors of a new study.

The work found that pedophiles are more likely to have certain types of superficial facial flaws, known as minor physical anomalies, and to be left-handed.

This adds to a growing body of evidence that suggests pedophilia develops around the same time that such physical traits do—in the womb, said study leader Fiona Dyshniku of the University of Windsor in Canada.

The findings are published in the journal Archives of Sexual Behavior.

“Evidence is steadily accumulating to support a neuro-developmental basis of pedophilia,” said Dyshniku. “If we find that pedophilia has a biological basis, with a very early, even prenatal onset, this will influence and hopefully improve methods of treatment for this group.”

Facial anomalies could, among others, include having non-detached earlobes, malformed ears, or a high or “steepled” palate, she said.

These features develop during the sensitive first and early second trimesters while a baby is still in the womb, she explained. They come from the same layer of embryonic tissue, the “primary,” that gives rise to the central nervous system, including the brain. Such anomalies could develop because of prenatal exposure to viruses, alcohol or drugs, obstetric complications, or nutritional deficiencies, she added.

Such features are more prevalent among men, she continued, which might mean that the male brain is more susceptible to such disruptive events.

“For years, it was thought that child molestation was somewhat of a learned behavior, potentially from the abusers having been sexually abused themselves as children. While this may be a factor in some cases, this is not the case in those with genuine pedophilia,” said Rachel Fazio, a clinical neuropsychologist and co-author of the study.

The researchers said they studied 140 consenting participants who had been referred to the Kurt Freund Laboratory of the Centre for Addiction and Mental Health in Toronto to be assessed for distressing or illegal sexual behavior.