This was something that was brought up in one of my classes. Can someone be excommunicated for being a homosexual?

There are a few offenses for which Latin Rite Roman Catholics are automatically excommunicated (the Latin term is Latæ Sententiæ):
• Apostasy - the formal renunciation of one's religion, especially if the motive is deemed unworthy
• Heresy
• Desecration of the Eucharist
• Physical force against the Pope
• Attempted sacramental absolution of a partner in adultery
• Ordination of a bishop without a Papal mandate (e.g. all bishops in the government-run Chinese Patriotic Church)
• For non-electors present in the conclave, revelation of the details of the conclave
• Simoniacal provision of the Papal office
• Violation of the sacramental seal of confession by a priest or bishop
• Procurement of a completed abortion

Remember the purpose of excommunication is the correction and redemption of the person who has chosen to separate himself or herself from the Church.

For more information, see: http://www.newadvent.org/cathen/05678a.htm

+ Homosexuality +

Created in the image of the one God and equally endowed with rational souls, all men have the same nature and the same origin. Redeemed by the sacrifice of Christ, all are called to participate in the same divine beatitude: all therefore enjoy an equal dignity.

The Catholic Church believes there is nothing sinful about being homosexual. But homosexuals like all unmarried people are called to celibacy.

The Church specifically says that homosexuals "must be accepted with respect, compassion, and sensitivity. Every sign of unjust discrimination in their regard should be avoided."

Here is the text of the document, On the Pastoral Care of Homosexual Persons (1986): http://www.newadvent.org/library/docs_df86ho.htm

For more information, see the Catechism of the Catholic Church, section 2357-2359: