The Catholic Church respects and loves the homosexual person the same as it does the heterosexual. Catholicism teaches that homosexual people must be treated with respect, compassion, and sensitivity. Every act or thought of hatred, violence, or persecution toward the homosexual is condemned.
The Church considers any and all sexual activity outside of marriage as sinful and immoral. Masturbation, fornication, adultery, pornography, and artificial contraception are all sins in the eyes of the Catholic Church.
The Church opposes same-sex unions based on Genesis 1:25–28: "God created man in his own image….male and female he created them… and God said, 'Be fruitful and multiply' " and Genesis 2:24, " a man shall be joined to his wife, and they shall become one flesh." Jesus himself uses these same quotation in Mark 10:6–9 when asked about marriage.
Catholics believe that marriage is the permanent, faithful, and God-willing fruitful union of a man and woman who have entered the covenant relationship of husband and wife. The sacrament of Matrimony is a sacred bond that imitates the love between Christ and his bride, the Church. The Church believes that because God instituted marriage, neither the Church nor the secular state (civil government) has the authority to redefine or substantially change the nature of marriage.
Despite the decision of some other Christian churches to accept openly gay ministers, the Catholic Church doesn't follow the same path. Just as it does not consider the restriction of marriage to one of each gender as being discriminatory against homosexuals, neither does it see the limitation of holy orders to hetrosexual males as being unfair.
The Church doesn't want and shouldn't ordain anyone who opposes official doctrine. A man who favors abortion is as unsuitable for the seminary as a man who favors artificial contraception or same-sex marriage or who denies the divinity of Christ or the perpetual virginity of Mary. So ordaining any man whose ideology or lifestyle conflicts with the faith and morals of the Church that he's expected to explain and defend is hypocritical and impractical.