Should employers match enhanced maternity pay under Shared Paternal Leave?

April 2015 saw the reshaping of family-friendly leave with the birth of Shared Parental Leave (ShPL). A mother can elect to curtail their maternity leave period two weeks after giving birth. She can then elect to convert the unused portion of that leave, so that up to 50 weeks' statutory leave and 37 weeks' statutory pay can be shared between both parents. BUT can employers offer enhanced contractual maternity pay to mothers for those 50 weeks, but only statutory shared parental pay to fathers?