Both are considered to be grave sins, and BOTH are considered to be morally disordered.
CCC2351 “Sexual pleasure is morally disordered when sought for itself, isolated from its procreative and unitive purposes”
The above also defines heterosexual sex outside marriage ((which is considered to be fornication) and use of artificial contraception (both inside and outside of marriage) as disordered.
CCC 2396 “Among the sins gravely contrary to chastity are masturbation, fornication, pornography, and homosexual practices”. To be guilty of any of these offences, unrepented, bars you from receiving Communion. Homosexual acts are not singled out as being worse than the others.
Both homosexual sex, and heterosexual sex outside marriage represent a complete separation from God, both equally bar the unrepented sinner from receiving Communion. A heterosexual person who is living with (and having sexual relations with) a person of the opposite sex receiving Communion is just as wrong as a homosexual man living with (and having sexual relations with) another man and receiving Communion. Both are barred from doing so.
We need to be very careful that, when taking a stance against homosexual acts, we also take an equal stance against heterosexual acts outside marriage. To fail to do so is to be guilty of prejudice and discrimination.
"2357 … Basing itself on Sacred Scripture, which presents homosexual acts as acts of grave depravity,141 tradition has always declared that "homosexual acts are intrinsically disordered."142 They are contrary to the natural law… "
See, but I do not think that pointing out that homosexual acts are intrinsically disordered is discrimination or prejudice (the reason intercourse outside of marriage is morally disordered is not because of the type of act, the type of act is not intrinsically disordered, but because it is outside marriage, thus making use of sexuality for the wrong reasons.)
Of course they are both wrong, of course we should not receive Communion if we have participated in either act, but this does not mean that both acts are identical. I think it is helpful to identify the fact that they are different.
Part of the campaign going on out there is effort to equate homosexual acts to heterosexual acts, but they are simply not the same. The Church recognizes they are not the same, there is no prejudice in this.
“(also from 2357) They do not proceed from a genuine affective and sexual complementarity. Under no circumstances can they be approved.”
The Church talks against prejudice as well; about love and compassion:
“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.
2359 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.”
