As a Catholic, I always look to the Catechism for guidance when it comes to questions like these. The Catechism covers the topic of homosexuality in CCC 2357-2359, but the pertinent section for a question like this one, to me, is 2358, which reads as follows:
2358 The number of men and women who have deep-seated homosexual tendencies is not negligible. This inclination, which is objectively disordered, constitutes for most of them a trial. They must be accepted with respect, compassion, and sensitivity. Every sign of unjust discrimination in their regard should be avoided. These persons are called to fulfill God's will in their lives and, if they are Christians, to unite to the sacrifice of the Lord's Cross the difficulties they may encounter from their condition.How does this relate to the topic of Elena Kagan, and the question as to whether her sexual orientation is pertinent to her qualification to serve on the Supreme Court?
In the first place, it should be noted that Kagan's orientation is not known; she is described as single. If she does suffer from same-sex attraction she has not chosen to embrace or live the active homosexual lifestyle openly. It may be that she is not attracted to her own gender at all, and that suspicions in this regard are unjust or even uncharitable; but if news were to break tomorrow proving that Kagan has (at least at some time) lived such a lifestyle this would not change the fact that she has chosen to keep all such matters private. This is relevant for one reason: while there may be certain jobs which would be better not to be held by people openly living the homosexual lifestyle (jobs in which impressionable young children will be confused about gender identity, for one example) it is much harder to see the justice in doing so when the person in question is not openly living that life, nor speaking about it, etc. As the Catechism reminds us, we have a duty to avoid all unjust discrimination against those attracted to the same sex; and human dignity means that people should be given access to employment, as well as shelter, health care, and other ordinary aspects of life which are necessary for survival.
In the second place, I think that some might object that for a same-sex attracted person to serve on the Supreme Court would automatically mean that this person would take an activist's view of any Constitutional matters pertaining to homosexual issues, such as gay marriage. The truth is, merely being attracted to one's own gender would not necessarily make a Supreme Court justice rule unfairly in favor of the same-sex attracted community; it is possible to imagine a conservative Catholic judge who is secretly attracted to his own gender, but who struggles with that attraction through frequent Confession, Mass and frequent reception of Holy Communion, and positive habits of thought and action. Such a judge would not be inclined to rule unfairly in favor of homosexual activism or to interpret the Constitution in ways that would privilege this group--but the opposite is also true, in that a married heterosexual judge who believes that two men or two women are capable of "marriage" might be more "gay-friendly" than the judge struggling with same-sex attraction. In other words, if Kagan has (as some have demonstrated) shown that her ideas might unfairly privilege homosexual activists, that is one reason to object to her nomination--but her sexual orientation, whatever that might be, is not the same as her ideas, as this example demonstrates.
Which brings us to the third point: there are plenty of reasons to object to Elena Kagan's nomination based on her experience (or lack therof), ideas, and possible judicial activism; I described some of them in my earlier post. Her hypothetical attraction to her own gender, which may not even be true, is not one of them.
Catholics need to witness to the teachings of the Church on homosexuality, including that teaching found in CCC 2358. All unjust discrimination against people who suffer from homosexual tendencies must be avoided. That doesn't mean that there aren't just reasons to object to the homosexual agenda, of course; marriage doesn't have to be redefined, children don't have to have their latency periods disturbed by conflicting messages about gender, society doesn't have to embrace homosexuality as the source and summit of wonderfulness (as Mark Shea sometimes puts it). But I think we should take care to keep from discriminating unjustly against people who might be same-sex attracted, by declaring that on that basis alone (regardless of lifestyle or ideas) they aren't qualified for a specific job in the public sector.