Part I

When a couple who had tried unsuccessfully for six years to have a baby naturally turned to one of the best known fertility clinics in the United States, they never imagined what would develop nine months later.

The couple studied their options and eventually opted for in vitro fertilization to increase their opportunities of having children. Technicians at the prestigious clinic extracted several mature eggs from Hannah’s ovaries after several weeks of mild hormone treatments. Two of Hannah’s ova (eggs) were selected and later fertilized with sperm from her husband. The fertilized eggs were then transplanted back into Hannah’s uterus to continue their development. The in vitro fertilization (IVF) occurred in March and the following December the couple excitedly awaited the birth of twins.

Hannah and Nathan Jones were ecstatic when healthy twin baby boys, Thomas and Darrell, were born.

The differences in the Jones’ twins weren’t that noticable at birth, but as the weeks passed and both infants started to grow, the parents watched in amazement as their children changed right before their eyes. One mellowed to a golden bronze and his dark hair turned curly, while the other displayed a milky complexion with straight, blond hair.

“Right after the birth it wasn’t obvious to us,” said Hannah, adding, “Thomas was a little lighter than Darrell. But after eight weeks I thought, this isn’t possible.” Darrell’s skin was quite dark, and he had a much flatter nose than his brother.

Questions

1. How are in vivo fertilization and in vitro fertilization similar? How are they different?
2. Are Darrell and Thomas fraternal or identical twins? How is the formation of fraternal twins different from the formation of identical twins?
3. In the time remaining, write down as many questions as you can that are raised by this story. Think of as many scenarios as you can that would lead to this situation.

Image Credit: Detail from “Slumber” by William-Adolph Bouguereau (1825-1905).

Date Posted: 10/20/03 nas

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