This is a weird one that I am helping my son to troubleshoot. This is what's happening.
We have setup his DroidX to connect with Facebook (providing his Facebook login and password) which also lets you synchronize your Facebook contacts with your Google/DroidX contacts. As you know, with a Google account you always have a record for yourself that typically starts with 'me' in the name. We allowed this sync to occur. All appeared to be fine.
This is where it gets weird. We then opened up the 'me' contact that represents his own contact information we found not only his own contact info but also someone elses phone number, email address, and date of birth as additional contact details in the same record.
I think I have discovered what appears to be happening. The other person (who's contact information is being erroneously added to my sons contact record, has the same name as my son. Yea, it's a very common name so it happens. He is also a 'friend' with this person on Facebook, therefore he has access to the contact information in this other persons profile. Apparently the functionality that synchronizes the Facebook contacts is picking up that other 'like-named' person and assuming it's my sons profile info. It's combining that with his real profile info on his DroidX phone.
I can think of some interesting tricks to do with this.... like getting specific profile data pushed out to someone else's address book without them knowing it. Hmmm.... working on testing a few ideas now.