My egg donor produced one baby, and her second donation resulted in another pregnancy.  My baby already would have two biological half siblings.  I could have played Sherlock Holmes and discovered the identity of these children.  Already there is a website for the 150 and still counting prodigy of a prolific sperm donor.  A mother of one of the children keeps track of the growing family tree so that in the future her son could meet some of his brothers and sisters.  I did not want built-in relatives that were complete strangers. I also did not want to jeopardize my position as the mother of my child by establishing relationships that were based on the biological egg donor mother.  But I would have been open to an incest website to prevent the growing possibility of an egg donor child of mine inadvertently marrying a half sibling. Of course, since many egg donor recipients never reveal their egg donor origin to their child, I still could have a grandchild born of incest.