Feature: Blood groups and parentage

I believe that this section arouses so much interest (and accounts for most of my emails) because of the last subsection - questions of parentage. My heart sinks when I get a request to comment on whether I think a particular reader's son/daughter is his/hers. It's not that I resent the question, naturally, but rather that the topic is so often fraught with painful emotion, no matter what reply you give. I can't obviously ever give a definite answer, but I do believe that the truth is a precious thing, and that comforting falsehoods aren't in the brief of this blog. So, I usually respond along cautious but truthful lines, and most people seem to appreciate it, even when the news isn't good.

All that said, I've actually written surprisingly little on the topic for the blog yet, but I promise to remedy that soon.  Relating to blood groups, there are three posts dealing with the matter, namely:

• What are blood types, and how many types are there?
• Which are the most common blood groups?
• How are blood types inherited and what does this say about parentage? (I've recently added a summary to the end of this article.)
• Can the ABO system be used to establish parentage reliably?

Then there's the topic of blood compatibility and transfusions, to which I'll have to give a decent answer soon. So far, we've just covered the rather peripheral issues of compatibility and platelets and graft versus host disease (whether or not the donor's blood can ever have the temerity to attack the recipient). There's also a clarifying section on the misleading terms "universal donor" and "universal recipient".

For other blood-related topics, have a look at the Haematology label on the left.