Geni is about Family History, not just Genealogy - so as far as Geni goes, no, you definitely do not have to throw out any of your info or profiles or etc. Also - geni now allows you to choose for a parent whether that parent is the biological or adoptive parent -- see info (and blog linked to) here http://www.geni.com/discussions/145776
Legally, I would think you are who you always thought you were!