pregnancy

Researchers say they can replace DNA in human eggs with genetic material from another woman to prevent devastating disorders in children. But big questions remain on safety and ethics.

Everybody knows that you're not supposed to smoke while you're pregnant because it's bad for the baby. But nicotine patches often used to help women quit may pose a risk, too, researchers say. Other forms of nicotine replacement may do less harm.

Pregnant women are told not to drink, smoke or stress out. But it hasn't been clear how those choices may affect a fetus. By studying how genes are turned on and off, scientists say they are getting closer to understanding what experiences in the womb really affect a child's health.

Many obstetricians make more money for C-sections than for vaginal deliveries. In a recent study, these doctors were more likely to perform the costly procedure than doctors paid a flat salary. But when the pregnant women were also physicians, doctors seemed less swayed by financial incentives.

The only women who have gotten pregnant with an ovarian transplant are cancer patients at great risk of losing their fertility. But a handful of doctors are now doing the procedure for patients trying to beat their biological clocks.