Not a joke, exactly, but a caricature. To paint it in broad brushstrokes that LDS would surely quibble over, the Mormons believe that good enough humans can become gods, that spirits have genders as well and marriage continues into the afterlife, and that human couples that become gods can go on to populate their own worlds with their spirit children.

Also, the angels are spirit-children of God too (like humans) and some humans were also, or will become, angels. Adam, for instance, was also the archangel Michael.