What a story! What a heartbreak! More Lone Star than Sideshow. Interestingly enough, the article focuses on a debate in the House of Lords about the use of in-vitro fertilization and sperm donors and the need for people to know their biological parents so they can avoid biological incest. They speak as if technology has made this a new risk.
And yet, when you think about it, we all have to trust our mothers as to who our fathers are. I'm sure there have been innumerable instances of siblings mating over the course of human history. Actually, the sociological side of it creeps me out as much or more than the biological. If two people raised as brother and sister find out they are not in any way blood relations and then want to get married, should that be called incest or not? It would make my skin crawl, but maybe it wouldn't bother other people. First cousins used to get married quite often—they still do in many cultures. But in the U.S., the thought makes us cringe.
That's one thing the Guardian article doesn't address. Did these folks want to have their marriage annulled or not? From other stories online, it sounds like they initiated the annulment. But apparently they also felt an immediate attraction when they first met. Apparently, it isn't only opposites who attract. And coincidence isn't always happy.