The old straw man suggests that if God is the source of created heterozygosity, then the model would not be scientifically testable.
It is not necessary to get God into the test tube, it is a question of how well the model of created heterozygosity explains the evidence. Jeanson has made many scientifically testable predictions and he put them in his book. When do you scientifically show that these predictions do not match the evidence?