If you used the program installed as an application on your own computer, only you have copies.
If you used Turbotax online, each return requires a separate account. Accounts can be linked to the same email address but have different user names and passwords. Use the account recovery link to search for additional accounts you might have.
If you only have one account, it is possible that you prepared one return in one person's name, then erased their info and over-wrote it with the info of a second person. (This is supposed to not happen but I am suspicious that sometimes it might.)
