Google tells me that gem squash is a c. pepo type while butternut are c. moschata species. They shouldn't cross, unfortunately. Some people complain about too many males due possibly to nitrogen excess. I don't know if it's possible to encourage vigorous vegetative growth to deliberately encourage male flowers, but it makes some backyard logic sense. Stress seems to encourage vegetables to favor pollen over fruit as well. General consensus seems to be generally that not much can be done, other than keeping the plants healthy, when underproduction of females is the common problem, so I wonder if disrupting roots and a little stress and vegetative growth is the solution to lack of males. In plant terms, I'd think a happy plant tries to flower and fruit in place, but an unhappy plant uses pollen and vining to move it's genetics to a hopefully better place.