Ok so it may have to do with the Rh factor. My husband is O neg- doesn't get bit or at least never enough to warrant DEET spray use. I am A pos and worried that all that Deet covering my arms/legs/neck all the time, absorbed through the skin is enough to be considered "chemical exposure" to trigger some mutagenic DNA twist=cancer. I'll have to look into that Rh factor vs biting insect attractive blood thing. I bet I'm not the first one wondering about that and there's some data on the netI'm ab negative too.
But pecs positive.