The beautiful child that comes out when you cross the beautiful btg with the very slutty margaret. the bestest/most pretty baby ever since jesus, hence the name.
Person: OH DEAR LORD WHOS BEAUTIFUL BABY IS THAT?
Margaret: Its mine, I had it with my gf, BTG.
Person: OH SLAP ME, ITS WONDERFUL, ITS A JESUS BABY
BTG: We get that alot
When your girlfriend who wont have sex with you is miraculously impregnated.
Guy 1: A fool, I see your lady's bump, ata boy. Guy 2: Well, we havent even done it, guess its a Jesus baby.