One of my most popular posts on this blog has been, "Giving Birth to Hairy Worms", all about the Renaissance belief in spontaneous generation (ie giving birth without the need for sexual reproduction). While the idea may seem far fetched, it turns out that spontaneous generation is in fact all around us. And it's called parthenogenesis.
In fact, it's right in my garden. The round things growing on my tree are oak galls. They are created by wingless, asexual female gall wasps, which are born from galls in the tree roots, created by winged females, who have mated with males. The tree galls hatch more wasps, which begin the double cycle again. So every other generation of female gall wasps will be asexual and wingless. The next generation will be sexual and winged.
Other creatures that reproduce asexually incude aphids, which produce exact clones of themselves, and a certain species of ant.
Amazingly, parthenogenesis is not limited to small creatures like insects. Something as big as a Komodo dragon is capable of reproducing asexually when there isn't a male around. But then it can change back to sexual reproduction when males arrive. Check out this site for more instances:
Imagine if this were possible for humans. How would it work in science fiction or fantasy? Would you like to have little clones of yourself? Could reproduction be brought on by looking at a picture of your ideal baby (or your ideal spouse)? What if people could change back and forth like the Komodo dragons? How would men feel about this, or would they be able to reproduce as well? What if we had a double life cycle, like the gall wasps? The possibilities are endless...