  We review the prospects for Central Exclusive Diffractive (CED) production of
Higgs bosons in the SM with a fourth generation of fermions at the LHC using
forward proton detectors installed at 220m and 420m distance around ATLAS and /
or CMS. We discuss the determination of Higgs spin-parity and coupling
structures at the LHC and show that the forward proton mode would provide a
critical information on the CP properties of the Higgs bosons.
