The Bishops’ Letter opens with a quotation from the Nuptial Blessing:

“Father, by your plan man and woman are united, and married life has been established as the one blessing that was not forfeited by original sin or washed away by the flood.” (Nuptial Blessing)

They follow this quotation with this statement:

Original sin introduced evil and disorder into the world. As a consequence of the break with God, this first sin ruptured the original communion between man and woman.  Nonetheless, the original blessing of marriage was never revoked.  (2)

This opening salvo couldn’t be more different from the modern sexual revolution.  Marriage is a blessing. The world created by God is good, until evil enters the world, through original sin.  The differences between men and women are not evidence of some cosmic injustice that we, the all-knowing, all-wise moderns, are destined and indeed required to repair.  Nor are the differences between men and women some kind of cosmic oversight or mistake on God’s part.  The differences between men and women are designed by God to allow us to be in communion with each other, that is, with someone like ourselves and yet structurally distinct. The rupture between men and women is not the way things are supposed to be, but rather a consequence of original sin.

Read it all here.