Most C&B top spots are guys. The nature of the job is more analytical (numbers etc), which most guys are better in.

Stop thinking of HR as admin. HR =/= the receptionist
Maybe Shared Services would be mostly females because they are employee-facing, but HRSS is kind of broad.

I guess it's mostly fair game in the specialist fields, eg rewards, training, processes, HRIS.

p.s I'm a female doing C&B for 3 years.