One thing just crossed my mind: Anakin didn't know the sex of his child, so it could have been a girl, right? So, why didn't he get suspicious about Leia? I have mentioned this before...

Vader visits Alderaan.

Vader: "Bail Organa. We meet again."
Bail: "Indeed. Anak...uh.... Lord Vader, this is my daughter, Leia Sk... Leia Organa. She is 5 years old."
Vader: "I didn't realize your wife was preagnant. At all. At any time. In fact, there are no records of..."
Bail: "Oh well, she... uh... she wasn't preagnant, you see, we adopted her."
Leia: "Whaaaat? Waaaaaa!" * runs away crying *
Vader: "I see. And may I ask where did you find her?"
Bail: "Oh I don't know, on the street, now let's talk about politics, shall we?"
Vader: "Very well."