Lesbian and bisexual women are more likely to report childhood abuse and adult sexual assault than heterosexual women, according to a new study.

Researchers found that women who described themselves as being more "butch" report more abuse in childhood, particularly physical and emotional neglect, whereas women who identify themselves as "femme" and have a more feminine appearance report more adult sexual assaults.

Researchers still not fully understood why sexual minority women are at greater risk of being abused both as children and adults compared to heterosexual women.

The study, published online in the journal Sex Roles, was based on data from the Rainbow Women's Project in the US a national, web-based survey of adult women who identify as lesbian and bisexual.

Researchers looked at answers from a total of 1,243 adult sexual minority women had completed an anonymous Internet survey and examined whether reported experiences of childhood abuse and adult sexual assault differed among sexual minority women of varying gender identity including, butch, femme, androgynous, or other gender expressions.

The term "butch" and "femme" refers to masculine and feminine gender identities within lesbian and bisexual communities, and the term "androgynous" refers to "soft butch" and is more similar to a "butch" aesthetic style rather than "femme".

They found that 40 percent of the respondents identified with the term "femme" and 15 percent with the term "butch".

"The sexual minority women in our sample reported high rates of childhood abuse and neglect and adult sexual assault. Women who described themselves as more butch reported significantly greater childhood emotional and physical neglect," researcher Dr. Keren Lehavot from the VA Puget Sound Health Care System in Seattle, said in a statement.

"Those who identified themselves as more femme reported significantly more forced adult sex. Given the gravity of this widespread problem, identifying the most vulnerable among this group is critical. Clinicians and providers working with sexual minorities should consider the role of gender identity and expression in targeted assessments and interventions," Lehavot added.