At the end of episode 3, Senator Bail Organa brings a baby girl back to his home planet Alderaan. He and his wife, Breha, adopt the girl and raise her in the royal family. He even kept the baby's birth name, Leia.
This other question asks if Bail Organa told his wife about the baby's parentage, but I want to know what the royal family told everyone else.
Since royal families are publicly known, how did the royal family explain to the public where the baby came from? If Bail Organa said the child was adopted, wouldn't people be curious about the child's origins? If he said the child was related to the royal family, wouldn't people be able to figure out that was false since they would (probably) know all the members of the royal family? Did he say the child was his by another woman? (Eddard Stark got around the questions by saying "Jon Snow is my bastard child." I can imagine Bail Organa saying something similar.)
If I was a Sith Lord and emperor, and one of the senators just announced a new adoption, and I knew that senator was friendly with a pregnant senator who just died under mysterious circumstances, I would send people to investigate the origins of baby Leia Organa.