The advantage of a fence is that the vines will produce fruit free of blemishes and stains. If a trellis is used, be sure it will support lots of weight. A plant full of gourds is very heavy. A ten pound gourd weighs only one pound after it is dried. I have had 10-12 gourds on one plant.
Male blooms grow on the main vines.
When the main vine gets to about 10-12 feet in length, trim it. Females blooms will start to grow on the side shoots. The gourd plant has male and female blooms. Both are funnel in shape but the female has a small round bulb at the base of it's bloom. Male blooms develop two weeks before the female.