Jennifer Estep has never been diagnosed with breast or ovarian cancer. Yet, the 37-year-old mother of two has had her breasts and ovaries surgically removed.

Estep, of Cooper City, is one of many women who have had preventive, or prophylactic, surgery after a test showed they carried a genetic mutation that significantly increased their risk of developing breast and ovarian cancer.

Indeed, a study of 2,677 women in nine countries who tested positive for BRCA 1 or BRCA 2 — gene mutations that significantly increase a woman’s risk of developing breast or ovarian cancer — showed that many American women chose to have their breasts or ovaries removed once they learned they carried the genes.

Genetic testing and the BRCA gene mutations were thrust into the spotlight after actress Angelina Jolie revealed in a May 14th op-ed column in The New York Times that she had a preventive double mastectomy because she carried the BRCA 1 mutation. Jolie, 38, like many other BRCA-positive women, has a family history of breast and ovarian cancer. Her mother died in 2007 of ovarian cancer and her aunt recently passed away from breast cancer.

“That genetic test made all the difference in the world for me,’’ Estep said. “Without it, I would be sitting and waiting to get breast cancer.”

Maxine Chang-Chin, a cancer risk assessment counselor at Memorial Healthcare System in Broward, said Jolie’s choice has increased awareness about genetic testing.

“It opens up that conversation. Some patients heard about it and now called and said they want to have genetic testing done,” said Chang-Chin, who said at least five patients called recently to talk about genetic testing. “They are also saying, ‘You know what, I am more comfortable removing my breasts than I was before.’ It’s making them feel more comfortable because Angelina Jolie is young as well.’’

Dr. Olaf Bodamer, medical director at the Dr. John T. Macdonald Foundation Department of Human Genetics at the University of Miami Miller School of Medicine, said his laboratory has been getting a number of calls by women seeking genetic testing.

“I think there was an immediate spike following the story in The New York Times,” Bodamer said.

But, Chang-Chin and Bodamer noted, genetic testing is not for everyone.

Among those who should seek counseling on genetic testing:

• Women with a family history of breast cancer where multiple family members were affected.

•  Women diagnosed with breast cancer at a young age, usually from their 20s to 40s.

•  Women who have ovarian cancer or have a family history of it.

•  Women and men of Ashkenazi Jewish heritage (those with ties to Central and Eastern Europe and Russia), who have a family history of breast or ovarian cancer.

“Someone with a family history with any of those would be an appropriate referral for genetic counseling,” said Talia Donenberg, a board-certified genetic counselor at UM.

BRCA 1 and BRCA 2 mutations increase a woman’s risk for breast cancer by 60 to 80 percent. BRCA 1 mutations increase the risk for ovarian cancer by 30 to 50 percent; BRCA 2 mutations increase the risk by 20 to 30 percent, Donenberg said. In Jolie’s case, doctors estimated she had an 87 percent risk of breast cancer and a 50 percent risk of ovarian cancer due to BRCA 1. By having the mastectomy, her chances of developing breast cancer dropped to under 5 percent, she wrote.