>>16700279
Do understand what imprinting is? it means that certain genes get disabled depending on the parent, that is some genes are only active from paternal chromosomes, while some are only active from the maternal chromosomes.
Two sperms, even from different persons, will have the same pattern of male imprinting and thus the same genes disabled on the same loci and so it would result in deficiencies of these genes resulting in imprinting disorders.

Having paternal uniparental disomy across all chromosomes would be a disaster and is actually exactly what happens in the case of a complete H. mole.