If you are a woman of childbearing age--even if you're not planning on having a baby soon--tear out this headline and stick it on the fridge. For years, doctors have been telling young women to take 400 micrograms daily of folic acid (vitamin B9), which comes in many multivitamins and can prevent spina bifida and neural-tube defects in babies. But women haven't listened; less than a third of them follow orders. Why? A new March of Dimes study says most simply forget about it, don't care or think it's only for pregnant women. Ladies, listen to us: few links are as strong as that between birth defects and folic acid, which works best if it's taken before pregnancy. And half of all U.S. pregnancies are unplanned. So if there's any chance you'll ever have a baby, get to the health-food store.