Diphallia is a rare medical condition in which a male infant is born with two penises.
Does brit-milah requires both penises to be circumcised? Is there any reference in the litterature about such an event?
The Rambam in Mishna Torah Hilchos Milah 1:7 says that someone who has 2 Orlos they make the Bris for both on the 8th day.
ומי שיש לו שתי ערלות, מלין את שתיהן בשמיני.
The Aruch HaShulchan Yoreh Deah 262:13 and the Sefer Minchas Ani - Hilchos Milah 13 says that although the Bris is done on the 8th day by such a child it would not be done on the 8th day if the 8th day is Shabbos.