Well it looks like both parthenocarpy and gynoecious traits are complex in cucumber - influenced by hormones so of course all the genetic makeup in the hormone aspect also plays into its expression, as well as the environment.
Here's a reference, hope the link works. Gynoecious flowering discussed page 7-8 and parthenocarpy page 9.
cuke.hort.ncsu.edu/cucurbit/wehner/articles/book15.pdf