Do Catholics psychologists have a moral obligation to treat homosexuality as a perversion? I was reading today about the Governor of New Jersey acting to ban "Gay Conversion Therapy", and wanted to know if this is just one more thing that Catholics would have a moral obligation to oppose.

The Catechism is clear in its stance, but vague in what it requires that people do when it says that the act is intrinsically disordered, but unjust discrimination is to be avoided.

So, to boil it down, is what the media calls Gay Conversion Therapy tantamount to unjust discrimination or is it a corporal work of mercy?
According to a statement made by The Catholic Medical Association in November of 2000, gay conversion therapy is considered a corporeal work of mercy.

This statement clearly points out that Catholic therapists are obligated to encourage chastity in all situations. The Church has always taught (and will always teach) that chaste behavior is required for spiritual health and well-being. 


  It should be pointed out that Catholics cannot support forms of
  therapy which encourage the patients to replace one form of sexual sin
  with another. (Schwartz 1984) Some therapists, for example, do not
  consider a patient "cured" until he can comfortably engage in sexual
  activity with the other sex, even if the patient is not married.
  (Masters 1979) Others encouraged patients to masturbate using
  other-sex imagery. (Blitch 1972; Conrad 1976)  Catholic therapists
  working with Catholic individuals should feel free to use the wealth
  of Catholic spirituality in this healing process. Those with father
  wounds can be encouraged to develop their relationship with God as a
  loving father. Those who were rejected or ridiculed by peers as
  youngsters can meditate upon the Jesus as brother, friend, and
  protector. Those who feel unmothered can turn to Mary for comfort. 
  (Homosexuality and Hope, part I, sect. 5-6)


As you pointed out, the CCC is clear about the chastity of those afflicted with same-sex attraction:


  Homosexual persons are called to chastity. By the virtues of
  self-mastery that teach them inner freedom, at times by the support of
  disinterested friendship, by prayer and sacramental grace, they can
  and should gradually and resolutely approach Christian perfection.
  (CCC 2359)


The Church, as well as the CMA, teaches that anyone with any type of sexual disorder (i.e. masturbation, adultery, homosexuality etc.) should be approached with nondiscriminatory therapeutic charity.  Where ever mercy is needed, the Body of Christ should be there.  


  The teachings of the Catholic Church on sexual morality are explicitly
  clear and do not allow exceptions. Catholics have a right to know the
  truth and those working with or for Catholic institutions have an
  obligation to clearly enunciate that truth.  Catholics must, of
  course, reach out to individuals experiencing same-sex attraction, to
  those actively involved in homosexual acts, and particularly to those
  suffering from sexually transmitted diseases, with love, hope, and the
  authentic, uncompromised message of freedom from sin through Jesus
  Christ. (Homosexuality and Hope, part I, sect. 5-6)


History has shown that whenever the Church makes a counter-cultural stand to defend her morals, she is always met with opposition.  This sometimes puts a heavy burden on those providing medical and psychological treatment. Nevertheless, the Church stays true to the Law of Christ, which is the Law of Merciful Love.  Catholic physicians and therapists are obligated to do the same.


  While any attempt to teach the sinfulness of illicit homosexual
  behavior may be greeted with accusations of 'homophobia', the reality
  is that Christ calls all to chastity in keeping with the particular
  state of life. The desire of the Church to help all live chastely is
  not a blanket condemnation of any who find chastity difficult but
  rather the compassionate response of a Church seeking to imitate
  Christ, the Good Shepherd.
  (Ibid.)