“…In keeping with an earlier suggestion (Giannelli 1986), I propose that the exclusion of sperm mitochondria from the zygote is part of a scheme enabling mitochondria to provide an indirect measure of sperm quality and, hence, to favor fertilization by optimal spermatozoa while avoiding the risk of passing on mtDNA exposed to high physiological stress and, hence, potential damage. This would clearly have adaptive value and could help justify the establishment of matrilineal mitochondrial inheritance.…”