Wherefore God also gave them up to uncleanness through the lusts of their own hearts, to dishonour their own bodies between themselves:
Note 2 at Ro 1:24: This phrase "God gave them up" is used twice in this passage (here and in Ro 1:26), and the phrase "God gave them over" is used once (Ro 1:28). These phrases are drawing on the fact that there is a God-given, intuitive knowledge inside of all people that would prevent them from committing such depraved acts (see note 2 at Ro 1:18). However, because of our free choice, God will not continue to force that restraint upon us against our will. If people persist in their rebellion against this conviction of God, He will give those people up to their own hearts' lust.
Therefore, those who are committing some of the terrible acts spoken of here (idolatry, homosexuality, etc.) and say that they have no conviction about it are either lying (Ro 1:18-20) or have been given over to a reprobate mind (see note 6 at Ro 1:28) by God.