I'm glad the 23andMe service allows people the option of learning about close relatives. But a couple of take home points:
1) If you get a 23andMe genetic test, make sure you really really want to know if you might have genetically close unknown relatives before you click through on that part of the results.Related: "Genetic testing brings families together. And sometimes tears them apart".
2) If you have a child you didn't tell your current family about, maybe you should come clean before you get your 23andMe test.