Praise be to Allah the Lord of the Worlds.
Books about the principles of Islamic jurisprudence state the conditions that must be met by a Mufti (An Islamic jurist qualified to issue a nonbinding opinion (Fatwa) on a point of Islamic law (Sharia) and a Mujtahid (an individual who is qualified to exercise ijtihad in the evaluation of Islamic law). However, nowadays, it suffices that a Mufti masters one of the four Sunni Schools of Islamic Jurisprudence and knows the rulings and their evidence from texts of Sharia. Moreover, the key regulator of Fatwa is Allah-Consciousness and knowing the evidence. As for new issues, some Islamic Fiqh academies were established to clarify their rulings on grounds of a joint effort exerted by a number of renowned scholars. And Allah The Almighty Knows Best.