According to the Catechism of the Catholic Church,
homosexual acts as acts of grave depravity, tradition has always declared that "homosexual acts are intrinsically disordered." They are contrary to the natural law [cf. CCC 2357], and the inclination to homosexual tendencies is objectively disordered [cf. CCC 2358].
This disorder, as the Church terms it, is not limited only to homosexuality. For example, the disorder in man, that say, leads to discord to the marriage union.
One comment in this article said,
My "natural action" has ALWAYS been homosexual [...]
Noting that to the online commenter, the inclination is "natural" to them, based on her faith, from where does the Church teach the disorder(s) in man comes from?
The answer will also define what "intrinsically disordered" means.