The forbidden relations of Leviticus [18 and 20] are among the most serious things in the Bible. They get up there with murder and idolatry. Together they make up the list of three things one must give up his life in order not to transgress. [I.e. in such a situation where one is given a choice]. There are plenty of other forbidden relations in Deuteronomy, but they are mere prohibitions. Not laws with the death penalty attached to them.
[There are exceptions which I ought to mention. My note above was just meant to give a general idea. Some exceptions are a menstruating woman. That is there is Leviticus, but without the death penalty. ]
[Maybe if people would learn the Bible, there would not be so much confusion about these issues.]
