Almost half of sexually active schoolgirls in New York have had female partners, according to a new study. Researchers from New York University and the Albert Einstein College of Medicine drew their conclusions from a survey carried out in 2013 which focused on public high school students, predominantly in "high-risk neighbourhoods" such as the Bronx, Brooklyn and Manhattan.

In the study, out of the 4,600 girls questioned 46.6% reported having same-sex relationships. The results will be published later in March in the Journal of Pediatric and Adolescent Gynaecology.

Researchers found that the "vulnerable population of girls" who take part in bisexual or same-sex activity are twice as likely as heterosexual teenagers to be sexually active, according to a New York Post report.

Other findings include that these young girls suffer more "intimate partner violence", have more sexual partners and start having sex earlier.

Young girls who report they are "not sure" of their sexual orientation are at highest risk of attempting suicide.

Emily Greytak an advocate for lesbian and bisexual youth called the study's results "disheartening, but not surprising".

Lesbian and bisexual girls are often stigmatised and treated with hostility, said Greytak, research director for GLSEN, a Manhattan-based group that promotes safe schools for LGBT students.

"That can lead to more risky behaviour, and takes a toll on their health," she said.

Greytak had four key recommendations for schools: anti-bullying and anti-discrimination policies, inclusive curriculums that are "reflective of the world" as well as supportive and trained educators.

"LGB youth need to see themselves reflected in the curriculum and non-LGB youth really need to see other people reflected in the curriculum as well to break down prejudice and barriers," she said in a Guardian report.

However, not all the teens who engage in same-sex relationships identify themselves as bisexual or lesbian, said Dr Chanelle Coble, NYU Langone Medical Centre, who co-authored the student with the Albert Einstein College.

"Just looking at how someone describes themselves doesn't tell the whole story," Coble said. "When they're young, it's harder for them to be specific about their identity – they're still exploring and figuring it out."