Transcript for Inside Angelina Jolie's Double Mastectomy Decision
She's battled CI -- assassins and evil scientists asked some movie star. But Hollywood a Lister and global activist Angelina Jolie is now waging a real life war against a disease that threatens to cut short the lives of millions of women. As ABC's Cynthia McFadden found it's her newly public battle against the risk of breast cancer that has turned her into a true inspiration for women around the world. Wherever she goes whatever she does Angelina Jolie captures headlines and -- -- like American. In some ways it seems you've used this sort of jujitsu move of celebrity. All of this enormous spotlight on you. His -- to a turnaround. On the other people who would otherwise get no attention. And that's good. The positive. And had slipped again I can do market with one -- once I went from. Famous for her stunning beauty and her -- movies like blocked off to me. An Oscar for girl interrupted and -- -- Just like you want. And preparing -- superstar Brad Pitt. Together and mr. and mrs. Smith and. And their six children. As an ambassador of goodwill in Africa and Cambodia and again today. With her op Ed piece in the New York -- and the stunning revelation that she had a preventative double mastectomy. She wrote. My doctors estimated that I and 87% risk of breast cancer. Once I knew this was my reality I decided to be proactive. And to minimize the risk as much as I could I've interviewed Angelina several times a few years ago after ovarian cancer took the life of her own beloved mother. At only 56. I don't -- Her. And. You know she's just she was just a very very loving person she was completely full of love and kindness. And it's the legacy that she left -- become a great actors she didn't. Become somebody anybody knew she didn't do anything other than love for children raise them with. With so much care and so she's taught me a lot about the importance of that and just being. Just -- just every day kindness. And them. And I think it's this from a subordinate being a mom. Today she said she is speaking out for her -- my children will never have the chance to know her can experience how loving and gracious she was. And asked the same could happen to me I've always told them not to worry but the truth is I carry a faulty gene. In February of this year Jolie underwent a major surgery an eight hour operation in which the breast tissue was removed before temporary -- Were put in place just six weeks later march 26. Angelina took a humanitarian trip to the Congo. Not telling her traveling companion in April 4 she attended the women in the world summit in New York. Appearing relaxed the next day she took -- -- shopping. Amazingly one of the world's most chronicled celebrities managed to keep her secret from the traps. Until today and that revealing -- On a personal note she wrote I do not feel any less of a woman. I feel empowered that I made a strong choice that in no way diminishes my femininity. -- tested positive for the gene called Rocco -- Women who carry these mutations have doctors say about a 65%. Risk of developing breast cancer. -- he and other women like her the choices are stark in 2005. Jessica -- it was a successful television writer. My mother had breast cancer which she beat. Seven years later she was diagnosed with stage -- C ovarian cancer. And she died two years after that I just decided you know -- actually just for peace of mind take the -- the results positive. Jessica was a high risk of developing breast cancer to mean breast cancer is the worst thing in the world I don't want to gamble with it. I don't want to gamble that maybe will catch it early enough. She decided to have to double mastectomy. Today eight years later Jessica is the mother to three year old Sophie. Who she had -- an anonymous sperm donor after nine attempts to become pregnant. My daughter is the -- of -- life I don't have words to express how much and that this little creature. Quello says Angelina Jolie is a role model. To the world. If you can walk around saying -- Angelina Jolie did it -- If your -- thirty year old mom and then that can give you a lot of confidence. Jessica braved all the medical procedures as a single woman. But Jolie underwent them with her partner Brad Pitt -- her side today -- issued this statement. Having -- decision firsthand I find -- -- choice as well as many others like her absolutely heroic. All I want is for her to have a long and healthy life with myself and our children. This is a happy day for our family. Jolie wrote we -- to -- moments to laugh together. We knew this was the right thing to do for our family and that it would bring us closer and -- hats. Jolie says she chose to share her story now wanting more women to get tested and know their options. Life comes with many challenges she wrote the ones that should not scare also the ones we can take on and take control -- And they can. Use this knowledge to make choices. Today in the Bronx we met Susan Klugman a doctor of clinical genetics for twenty years of money -- medical center. She counsels women about the risks of breast cancer and -- to consider surgery. And to make sure they have the insurance to cover it. Everyone has the bracket gene the way that the bracket gene functions is it protects you against breast cancer and ovarian cancer. If there's a change in that -- or a mutation. The patient loses that protection against cancer. And is therefore pre disposed I -- Angelina Jolie I think she was very brave and I think it's great what she's doing for women. Cancer is still -- did strikes fear in people's hearts Jolie wrote at least for her the chances of developing breast cancer are now just under 5%. I can tell my children that they don't need to fear they'll -- -- to breast cancer. And she looks forward to continuing the war. Traveling to the poorest and sometimes the most dangerous places on -- visiting the world's most vulnerable children and orphanages and refugee camp. You finally because and thank. You know my god that woman just crossed the border with five children and no food and and she's not complaining -- anything she just gets on so we have -- just -- Q what can I understand why do it now what why did you do it. -- be can't I think everybody. Needs a sense of purpose this -- to be useful there. You know I've been working on films are doing things try to work on my own career my own life and so. So certainly there was an emptiness in. Jolie as long fulfilled any sense of empty -- with empathy. She told now what it means to your mother. Six children three of them adopted. Just letting the kids know how much they make you happy. You know is is the great gift to give them other than. The disciplines important and all the support and what you give them in their schooling their education all have very important that the most important things to let them know. What a joy they are for you and what a pleasure it is to be their mind. As the world learned again today taking the lead -- Angelina Jolie has never shied away from. For Nightline I'm Cynthia McFadden in Tucson Arizona.
This transcript has been automatically generated and may not be 100% accurate.