Well Richard, if you're curious about your blood type, have you considered having a really bad accident so the ER can find out for you? That's the hard way. You mentioned, previously, you're not HIV positive (congrats!), maybe that same clinic could type your blood, since they have the data already. Heck, this could be selling point for your "desperate and dateless" situation. Sort of like, when another asks, "What's your sign?" You could say, "I"m type __________, are we compatible (ie: want to breed)?
RB - I'm just kidding with you 
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The ones who say “You can’t” and “You won’t” are probably the ones scared that you will. - Unknown