I've never worked with a male nursery nurse and I feel that's a shame. Anecdotally I've heard of several and I've worked with male playworkers and youth/camp leaders in regulated (playscheme type) and unregulated settings (like Scouting)
Firstly men provide a different kind of interaction and often have instinctively different approaches to play and communication - not making a value judgement on whether it's better or worse - just no matter what the activity whilst women nursery nurses and mothers will generally approach it in one way, fathers and male childcarers will have a different approach and I'm extrapolating that to a professional nursery environment. So they bring a new perspective which can have impacts on planning, activity provision, implementation and evaluation.
Secondly they're role models, not just as many in a caring profession but also they model male behaviour for boys to copy.
Third all female envirmonents get bitchy. Without exception the staff atmosphere has been better on playschemes where there's been a bloke in the room.
Fourth men are in childcare because they've made a concious choice to be, usually for the right reasons although sadly cases like this prove some people are in it for all the wrong ones. Women sometimes end up there and someone who wants to be there and is dedicated is a more positive influence than someone who ended up there because they could become a nursery assistant after leaving school in possession of 2 GCSEs and a uterus.
I could go on but then I'd be veering into the stereotypes of men being more sporty and energetic, which is a huge advantage in playschemes when you want to wear the kids out, or more confident to make fools of themselves, which is great for getting a group of reluctant cubs to join in, or more willing to get mucky, which is probably what the cubs wanted to do in the first place!