Levi Johnston says Bristol Palin's pregnancy was not an accident in tell-all book

Levi Johnston, 21, who fathered a child with Bristol Palin, the daughter of the former Alaska governor Sarah Palin, wrote a tell-all book about the Palin family, which is slated for release on September 20.

In his book, "Deer in the Headlights: My Life in Sarah Palin's Crosshairs," Johnston claimed that Bristol got pregnant on purpose because she was jealous of Sarah Palin's pregnancy with Trig. According to the Associated Press, in the book Johnston claimed Bristol told him in March 2008, "let's get pregnant."

The tell-all also contains several arguments to Bristol's book, "Not Afraid of Life: My Journey So Far," where his ex-girlfriend claimed she lost her virginity in a tent while drunk on wine coolers. Johnston claims that the two were sexually active long before the camping trip and that he tried to keep the alcohol away from her because she would "lose her judgment" when drinking.

He also said that Bristol's dad Todd Palin told him to quit school and get a job, while Sarah Palin wanted to adopt their baby as their own to "avoid a scandal."

In "Deer in the Headlights," Johnston also denies that he got another girl pregnant, as Bristol Palin told the media.

"I want to tell the truth about my close relationship with the Palins," Johnston said in a statement to People magazine in April. "My sense of Sarah and my perplexing fall from grace - how I feel and what I've learned... I'm doing this for me, for my boy Tripp and for the country."

Johnston has publicly spoken out against Sarah Palin in the past, speculating on her marriage difficulties and later apologized to the politician-turned-reality star and her husband Todd.

Johnston has said that abstinence is "not realistic" while Bristol Palin, the mother of their 2-year-old son Tripp, is a public speaker on abstinence and teen pregnancy. Bristol makes between $15,000 and $30,000 for each appearance and made headlines in January when students at Washington University protested her high appearance fee.

Bristol Palin was engaged to Johnston, 20, in 2008 and gave birth to Tripp that December at age 18. The two called then off their engagement, became engaged again in July 2010 and broke up weeks later.

Johnston famously posed for Playgirl magazine in February 2010.

Sarah Palin skewered Johnston in her book "America by Heart: Reflections on Family, Faith, and Flag," writing that it was "disgusting" to watch him exploit his sudden fame after she was chosen as U.S. Sen. John McCain's running mate in the 2008 presidential election.

Sarah Palin told CNN that she would announce whether or not she would run for president by the end of September. Though the Republican electorate does not support her candidacy, she has strong support from the tea party movement.

In August, Johnston announced that he plans on running for mayor of Wasilla, Alaska in the October 2011 election.