[One of the best and most competent recent summaries of the research…]

‘Enduring change to an individual ¢â‚¬â„¢s sexual orientation  is uncommon. The participants in this body of research  continued to experience same-sex attractions following  SOCE and did not report significant change to othersex attractions that could be empirically validated,  though some showed lessened physiological arousal to  all sexual stimuli. Compelling evidence of decreased  same-sex sexual behavior and of engagement in sexual  behavior with the other sex was rare.’

More -  http://www.apa.org/pi/lgbt/resources/therapeutic-response.pdf