We're Having a Cantaloupe!
You've got a heavyweight in your belly at 20 weeks pregnant (well, in baby terms, anyway). Your little champ weighs about ten ounces and has a height, crown to rump, of about six and a half inches. Think small cantaloupe (and probably as sweet too).
Is it a boy cantaloupe or a girl cantaloupe? You'll be able to find out your baby's gender via the ultrasound by this point. If you're carrying a girl fetus, her uterus is fully formed this week and her vaginal canal is starting its development (which means that in about twenty-five or thirty-some-odd years, she could be just where you're at, Grandma!). She also has primitive eggs in her tiny little ovaries now, seven million of them — though by the time she's born, that number will be down to two million (still more than she could ever hope to use). And interestingly, your baby girl will be born with all the eggs she'll ever have.
Have you got male? If your fetus is a boy, his testicles have begun their descent this week, though they're still located in the abdomen, waiting for the scrotum to finish growing so they'll have a place to drop into in a few weeks.
Though the external genitals in both male and female fetuses still have a way to grow, you should be able to find out the sex of your baby (if you want to) during an ultrasound exam.