Grimes and Elon Musk made a slight tweak to their newborn son X Æ A-12’s name on his birth certificate.The infant’s first name is X on the certificate, obtained by TMZ. His middle name is AE A-XII since birth names in California have to follow the English alphabet, excluding numbers and special signs.The “Delete Forever” singer, 32, gave birth to her first child and the entrepreneur’s sixth on May 4.