There can be no doubt that Jesus Christ rose from the dead, thereby demonstrating that He was fully man and is fully God.
God gave the Law, including marriage restrictions to Moses about 3,500 years ago, the biological reason did not become apparent until the relatively recent science of genetics revealed it.
There is no doubt that the man known in the Bible as Jesus of Nazareth was/is God the Son and that He rose from the dead.
The question is; Why 400 years between the testaments? But when we look at it closely, it all makes perfect sense.