It is harmful to go against God. Human nature, remember has a ‘fallen’ element.
But rather than me speaking or giving my answer, here are some resources:
Concupiscience: (Catholic encyclopedia)
In its widest acceptation, concupiscence is any yearning of the soul for good; in its strict and specific acceptation, a desire of the lower appetite contrary to reason. To understand how the sensuous and the rational appetite can be opposed, it should be borne in mind that their natural objects are altogether different. The object of the former is the gratification of the senses; the object of the latter is the good of the entire human nature and consists in the subordination of reason to God, its supreme good and ultimate end. But the lower appetite is of itself unrestrained, so as to pursue sensuous gratifications independently of the understanding and without regard to the good of the higher faculties. Hence desires contrary to the real good and order of reason may, and often do, rise in it, previous to the attention of the mind, and once risen, dispose the bodily organs to the pursuit and solicit the will to consent, while they more or less hinder reason from considering their lawfulness or unlawfulness. This is concupiscence in its strict and specific sense. As long, however, as deliberation is not completely impeded, the rational will is able to resist such desires and withhold consent, though it be not capable of crushing the effects they produce in the body, and though its freedom and dominion be to some extent diminished. If, in fact, the will resists, a struggle ensues, the sensuous appetite rebelliously demanding its gratification, reason, on the contrary, clinging to its own spiritual interests and asserting it control. “The flesh lusteth against the spirit, and the spirit against the flesh.”
newadvent.org/cathen/04208a.htm If you wish to study it further.
Specific to homosexuality; be it ‘human nature’ or an inclination one is born with as I’m assuming you mean… are you asking is it harmful to go against it? .
Here is the Catechism of the RCC on this issue:
Chastity and homosexuality
2357 Homosexuality refers to relations between men or between women who experience an exclusive or predominant sexual attraction toward persons of the same sex. It has taken a great variety of forms through the centuries and in different cultures. Its psychological genesis remains largely unexplained. 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. They close the sexual act to the gift of life. They do not proceed from a genuine affective and sexual complementarity. Under no circumstances can they be approved.
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.
More if you wish to study that section further:
scborromeo.org/ccc/p3s2c2a6.htm
May God Bless You
