According to the Centers for Disease Control and Prevention, women who get pregnant through infertility treatments have a 37 percent chance of a multiple birth, compared to 2 percent in the general population. Clearly, for couples who have struggled to become pregnant at great expense, this is a grueling decision. Doctors in the field say multiple births are not how they define success. With all the hype and headlines that surround reproductive technology, many couples assume they will succeed at getting pregnant. But while pregnancy rates are rising, statistics show infertility treatments fail for most couples.
Scientists predict higher success rates.
They are close to finding ways of limiting the number of multiple births. Women over 40 should have more luck. For now, there's no question that thousands of couples have reason to celebrate Louise Brown's birthday. But as the technological advances proceed at their rapid pace, it's also clear the related ethical issues cannot be rushed to resolution any more than pregnancy itself. Cloning External sites are not endorsed by CNN Interactive.