What was the relationship between Mosheh's (Moses') Father and Mother and is this permitted or forbidden?

Answer From The Annual Reading Schedule - Week 14 Notes For Exodus: According to Exodus 6:20, Aharon (Aaron) and Mosheh's (Moses') Mother was his Father's aunt. This relationship, similar to Avraham marrying his sister, was not forbidden until later in Leviticus 18:12 and 20:19. At the time it appears to have still been permitted most likely due to the need for the population of the world to continue to grow, or for whatever other reasons are known to Yahweh but unknown to me. I do not see any evidence that the relationships such as these were forbidden prior to them being forbidden in Leviticus 18 and 20. They are definitely forbidden now.