Homosexuality as Abomination

The Hebrew word here is to'evah, and it is worth knowing how it is used rather than how it sounds in English. In Leviticus 18 it is not attached to the incest laws, which are a separate cluster about lineage. It marks a different category.
Heiser's account of that category is creation order. Not ritual impurity, and not - in his view - Milgrom's proposal that the issue is wasted reproductive seed, which he sets aside because Leviticus does not apply the word to other non-procreative acts. What the designation marks is a departure from how human sexuality was designed.
And he observes that the New Testament does not carry the legal machinery forward. When Paul takes the subject up in Romans 1, he does not cite Leviticus or its penalties. He reasons from creation.
Scripture links:
- Leviticus 20:13 - The prohibition, with the civil penalty attached to it under the Sinai covenant.
- Romans 1:26-27 - Paul's treatment, which argues from design rather than from the law code.
The word is strong. What it marks is a design claim, and that is the argument Paul picks up.