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I know mine since I've had two babies. I know that both my dd's are the same as me which is O-
Dh is also O- we found his out because we got him tested at the nurse because of the RH Negative procedures during pregnancy. They had changed the procedure by the time I had my second dd and they wanted to give me Anti-d at 28 and 34 weeks and I said I didn't need it because dh was also O- but the hospital wouldn't take our word for it so we got him tested.
We were told that Gp's don't test you just because you want to know there has to be a reason and this was our reason and they ok'd it. I don't think they make a note of a babies blood group at birth in their books. They do check the babies blood but I don't think any record is held. It's definitely not in the records held at your GP becuase I once asked years before I had children just out of nosiness and then of course dh asked but they couldn't tell him he had to get tested to find out.
Interestingly my mum was also O- as is my brother. And Dh's mum and brother are also both O-.
I'm A+ (on blood donor register) -- don't know about DH or DS. One of my parents is O+ and one is A+ but I can't remember which is which, so presumably I have an AO genotype and DS could be A, O or even AB depending on what DH is.