one on one

Just recently a couple got married and then found out that they were indeed brother and sister.
“Incest is considered taboo in nearly every human culture around the world, researchers have found. Yet as the 21st century waxes, questions about the behavior remain unanswered.”
“Where does our aversion to incest come from — genetics or society — and what's so bad about it, anyway?”
Incest is also taboo in the Bible.
“On the whole, the risk of incest in plants and animals generally outweighs any of its benefits. Because so-called higher organisms such as humans are susceptible to life-shortening genetic combinations … lower birth weights, increased embryo death and decreased fertility. (not to mention depreciating the quality of life if survival does happen)”
"A donor can be used to conceive up to 10 children"; according to Alton's Web site up to 25 children have been conceived from a single donor. "That greatly increases the chances of something like this happening again – closely genetically related people getting married."
“what's so bad about it, anyway?” The man who was head of the group that ‘decoded’ the human gnome called the DNA “the Language Of God”. May be the One who created the code knew that there would be problems so He included a note in His owners manual, “thou shalt not uncover The nakedness of thy sister …” Leviticus 18

“Consider the Westermarck Effect, which essentially says children who co-reside are much less likely to breed with each other when they reach adulthood "The Kibbutz communities in Israel are a good example,". Only weeks after birth, mothers give their kids to a "children's society" staffed by trained caregivers. People raised in the same community are much less likely to marry each other than someone from a neighboring area. An other example is arranged Taiwanese "minor" marriages, where parents would arrange a marriage for their daughter by handing her over to the future groom's household shortly after birth. "Compared to 'major' marriage arrangements, where a couple meets just before the wedding, minor couples had fewer kids,". "Minor couples frequently refused to consummate their marriage, so the fathers would stand outside their door until they did." Well, well, two ethics problems in one story. There IS something to be said for the family – by the proper definition, one dad, one mom, and their ofspring.
Seems that people who study DNA can’t give up the idea that it did NOT just happen.