In her new memoir, Not Afraid of Life: My Journey So Far, Bristol Palin reveals, among other personal details of her life, the story about losing her virginity to her ex-fiancé, Levi Johnston.

On that fateful event, the former Dancing With the Stars contestant writes how it all unfolded: The 20-year old—then a teen—was on a camping trip with Johnston and drank too many wine coolers. While she had no memory of what happened next, all she could remember was that she woke up in a tent alone and that she could hear Johnston talking to friends outside.

Despite the vow they made to wait until marriage to have sex again, the promise didn't hold. And when she got pregnant with their son, Tripp, it took eight at-home pregnancy tests to convince her she was with child. She said she had been on birth control for cramps and never expected to conceive.

When it came to being supportive, Palin wrote that Johnston was less than helpful, saying her beau’s only words of encouragement were, "Better be a (bleeping) boy."

Much of what she recounts about her boyfriend, who posed for Playgirl after their split, overlaps with her mother's 2008 run for vice president. In the book, Bristol relives the family’s trip to Dayton, Ohio, where then-Gov. Sarah Palin announced she would be running alongside Sen. John McCain. It was at the GOP convention that the media discovered Bristol was expecting.

Since having her son, Bristol has worked as a spokeswoman to help prevent teen pregnancy. She also has her own reality show coming up on the Bio channel.

But don’t think her memoir is the last word on the matter of Levi. Mr. Johnston’s book, Deer in the Headlights: My Life in Sarah Palin's Crosshairs, is due out in the fall.

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