I thought they were a gourd myself but, before I made my little joke, I decided to do some research to make sure I didn't get it wrong and it turns out I still may have. Pumpkins, squashes and gourds are all part of the Cucurbitaceae family and, while some may set the pumpkin aside from the squash family, scientifically it does seem to be considered as a part of the Winter Squash subspecies. However, there are differences with the pumpkin to argue it doesn't belong as a cultivar or subspecies of the squash species because of the shape of its stem and it is the only squash to have edible seeds. Since I saw a couple sources listing the pumpkin on its own from gourds and squash I thought I was in the right but, looking into it some more, it seems pumpkin would be classified with squash.