Actual change in Sexual Orientation is documented in professional literature since the late 19th century.
There are many clinical studies and individual reports of people who, of their own free will, change their sexual orientation.
· Dr. Robert Spitzer, renowned psychiatrist, reported in a 2003 peer reviewed study, that 200 participants had reported a change from homosexual to heterosexual orientation.
· Sinead O’Connor, Pop star who was once a lesbian, fell in love with a male and married him.
· Donnie McClurkin, Grammy award winning gospel singer and evangelist, after 20 years living as a homosexual, is now a heterosexual.
· Greg Quinlan, PFOX President, lived as homosexual for 10 years, and then chose to leave homosexuality 17 years ago and become heterosexual.
Many Medical Professionals agree that sexual orientation is neither innate, inborn nor immutable-- Sexual orientation is more fluid than fixed.  “There is no consensus among scientists about the exact reasons that an individual develops a heterosexual, bisexual, gay or lesbian orientation.” 
What is successful change in sexual orientation?
“Like other challenges, success[in changing sexual orientation] is defined along a continuum ranging from a change in behavior to the reduction or even the elimination of unwanted homosexual attractions as well as changes in sexual orientation and sexual identity. [Emphasis added] Change might also include improved sense of self or an increase in security, a decrease in depression or hopelessness, as well as improvements in many other areas. …homosexuality is not invariably fixed in all people. Some people can and do change. And this change occurs not just in terms of identity but in core features of sexual orientation such as fantasy and arousal. The Spitzer Study, Hershberger's analysis of the Spitzer study, and the Karten study provide scientific support that change indeed does occur for some people.” Success rates for changing sexual orientation range from 30-70%, which is similar for the treatment of depression, substance abuse, and eating disorders.
There are NO existing studies that document sexual reorientation therapies as harmful! 
However, there is documentation and supported studies from the Federal Government, Gay and Lesbian Health Organizations and other health organizations, such as the American Medical Association, that establish that homosexual men and women have greater health risk factors such as life-threatening risk-taking of unprotected sex, substance abuse, sexual addiction and personality disorders; and these are about three times the prevalence versus those found in the general population—and sometimes much more. According to the Center for Disease Control (2010), the rate of new HIV diagnoses among men who have sex with men (MSM) is more than 44 times that of other men and more than 40 times that of women. There is even a Federal ban on gay men donating blood because of their high HIV/AIDS risk.
 National Association for Research and Therapy of Homosexuality (NARTH) Scientific Advisory Committee (2009). What Research Shows: NARTH's Response to the American Psychological Association's (APA) Claims on Homosexuality. Journal of Human Sexuality, 1, 1-128 http://www.narth.com/docs/journalsummary.pdf
 Spitzer, R. L. (2003). "Can some gay men and lesbians change their sexual orientation? 200 participants reporting a change from homosexual to heterosexual orientation," Archives of Sexual Behavior, 32, 5, October, p. 403-417.
 American Psychological Association, Ethical Principles of Psychology and Code of Conduct 57 AMERICAN PSYCHOLOGIST 1060 (2002), Principle E
 Personal communication, Chris Doyle, PFOX board member
 National Association for Research and Therapy of Homosexuality (NARTH), Scientific Advisory Committee (2009).
 American Psychological Association., (2008).Page 2, Answers to your questions: For a better understanding of sexual orientation and homosexuality.
 Hamilton, Julie (2010)
 National Association for Research and Therapy of Homosexuality (NARTH) Scientific Advisory Committee (2009).
 Sutton, Philip (2010), “CDC Analysis Provides New Look at Disproportionate Impact of HIV and Syphilis Among U.S. Gay and Bisexual Men Summary” http://www.narth.com/docs/disproportionate.html
 Centers for Disease Control and Prevention (2010), CDC Fact Sheet, http://www.cdc.gov/nchhstp/newsroom/docs/HIVandAIDSinAmericaSnapshotFINAL70710508COMP.pdf
 http://www.washingtontimes.com/news/2010/jun/11/panel-votes-keep-restrictions-gay-blood-donations/, Restrictions on giving blood by gays continue