Abstinence denial refers to two phenomena, deliberate denial by liberal and pro-abortion groups of the efficacy of abstinence-only programs in preventing disease, and denial from ignorance by those who have been convinced by the propaganda.
Liberals claim that abstinence pledge campaigns are ineffective when compaired to programs that involve both abstinence and information about a variety of birth control methods. However, surely numerous studies disprove this.
Groups such as Planned Parenthood have enormous interest in promoting sexual promiscuity, as their profits rely on it. Likewise, pharmaceutical groups selling drugs such as Gardasil and various forms of birth control cannot profit when abstinence is used.
The liberal entertainment industry relies on immoral consumers to purchase its products with immoral sexual content (television, film, etc.) Denying abstinence's efficacy is thus part of a wider attack on Christian morality. 
- Stanek, J. "True confessions of Planned Parenthood" WorldNetDaily; August 2, 2006 
- The Heritage Foundation, The Effectiveness of Abstinence Education Programs in Reducing Sexual Activity Among Youth, by Robert E. Rector, April 8, 2002