In an open letter, which has been signed by a number of bishops and archbishops, they encourage him to stick to the traditional teachings on divorce and gay marriage.
It's been written ahead of a key Vatican Synod in October.
In the appeal, they say: "Our fears arise from witnessing a decades-long sexual revolution promoted by an alliance of powerful organizations, political forces and the mass media that consistently work against the very existence of the family as the basic unit of society.
"Ever since the so-called May 1968 Sorbonne Revolution, a morality opposed to both Divine and natural law has been gradually and systematically imposed on us so implacably as to make it possible, for example, to teach the abhorrent 'gender theory' to young children in many countries."
Calling on him to clear up "confusion" over whether the Church will allow divorcees to take Communion and permit gay marriage, they say: "Truly, in these circumstances, a word from Your Holiness is the only way to clarify the growing confusion amongst the faithful.
"It would prevent the very teaching of Jesus Christ from being watered-down and would dispel the darkness looming over our children's future should that beacon no longer light their way."
Pro-life group SPUC is supporting the letter. Speaking to Premier, spokesman Matthew McCusker said: "If we look at lots of studies - we see that the marriage of one man and one woman is the safest place for children to be conceived, born, brought up.
"Anything we can do to strengthen the family based on marriage is at the heart of our work."
Pope Francis has already made his objection to same sex marriage clear but once said he was not in a position to judge gay people.
Listen to Matthew McCusker speaking to Premier's Antony Bushfield: