I’d like to see the results replicated and corroborated. Wi-fi is low power microwave radiation and shouldn’t be able to damage DNA, especially since only ionizing radiation (e.g. ultraviolet) has been proven to do that. Killing sperm, OTOH, can be explained by the fact that sperm is sensitive to heat (which is why it’s usually contained in a sack of flesh and skin outside the main body) and microwave radiation can heat things better than plain white light.