Although people with haemochromatosis tend to have higher than average Hb levels (probably because they never suffer from iron deficiency which is fairly common), unlike polycythaemia vera, the hamoglobin levels don’t get high enough to cause damage per se. It’s the iron deposits from excess iron which directly cause organ damage.

Research has shown that the methylation pattern of sperm changes with age. Methylation is an epigenetic phenomenon which determines whether sequences of DNA are active or silent. The methylation changes are observed in sequences thought to affect neurodevelopment (increasing the risk of autism and schizophrenia) as well as increasing cancer risk. https://www.nature.com/articles/s41598-020-80857-2