“Family Ties Are Probed At the Border,” The Wall Street Journal, March 3, 2018 A3. People claiming to be family are probed on information on accompanying children.
Of course your son’s birthday is information. If you don’t know that, are you more or less likely to be his father/mother?
If you’re the government agent, how do you determine if the relationship is legitimate? What information’s important? How do you verify?