Men and Women bring different things to the table. What makes a well rounded child is the different views and examples surrounding him/her.
I identify with my mother not my father. Not saying that my father was a bad model but, that I am a women and I identify with another women. My point being that, scouting should be of a diversified bunch. Even though I identify with my own gender I do use my fathers exapmles for choosing a mate or other males in my life. So yes you do need both men and women in such organizations that involve children. Not all children will be blessed with good role models at home. Because you never know that scout mom or scout dad might just be the one that influences that youth for the rest of his/her life.
On a different note... I am the cc of my pack and all positions but one are filled with women. In this day and age it is very hard to get the parents to even slow down while letting the kids out of the car. Never mind getting them involved. So in a perfect world you would have an equal amount of participation. But this isn't a perfect world. You take almost any warm body you can and be thankful for it. Because with out the volunters that we have, whether they be men or women, we wouldnt have a pack or troop.