Consecrated Sphinx

• WWizards of the Coast2017-11-17
  Official Ruling
  The ability triggers once for each card an opponent draws. You choose whether to draw two cards as each of those abilities resolves.
• WWizards of the Coast2017-11-17
  Official Ruling
  If each player controls a Consecrated Sphinx, their abilities will cause each other to trigger until one player chooses not to draw cards.
• WWizards of the Coast2017-11-17
  Official Ruling
  You may either draw two cards or not draw at all. You can't choose to draw only one card.

Rulings via Scryfall