In the Vedic understanding, the concept of "Dharma" is very significant. In creation, everything has its "dharma" or its intrinsic nature, which nature is inseparable from duty….To perform sex acts which are forbidden (and the same ones are forbidden in the Vedas, since such moral absolutes are coming from God wherever they are found) is to act against one's dharma as a human man or human woman. It is against nature, and against one's moral duty, one's duty to God to behave as He wants one to.
Romans 2:14-15 For when the Gentiles, which have not the law, do by nature the things contained in the law, these, having not the law, are a law unto themselves: Which show the work of the law written in their hearts, their conscience also bearing witness, and their thoughts the mean while accusing or else excusing one another;)
Exactly so. The Vedas further explain that God, in addition to His eternal existence in His spiritual Kingdom, is also in everyone's heart during their sojurn in the world of birth and death - and He is the source of the conscience, and the eternal law which is written in the core of everyone's heart. That is why His rules apply to everyone - even atheists, and why homosexuals will never be at peace even if they silence everyone who disagrees with or disapproves of their actions.