The March of Dimes has been campaigning for nearly 10 years for increased folic acid fortification of basic foods like flour and bread, and now they say why. (I'm sure they said why before, too; it's not like MOD is the Knights Templar or anything. Right? Right?) It helps drastically reduce neural tube defects (NTD) like spina bifida and anencephaly, which often occur in the earliest weeks of pregnancy.
People with uteruses can also get folic acid from vegetables and multivitamins, and people with uteruses, insurance and a hankerin' to use them can get it from pre-natal multivitamins, which are as big as your fist.
New research shows folic acid in grains has reduced birth defects [marchofdimes, via robotwisdom]
Folic Acid also reduces the chances split clef (as many people call hair lip).
I prefer Flinstone's vitamins, myself. :)
I've been telling people with uteruses & of childbearing age (any who will listen to me) for a while now that it's important to take a folic acid supplement... a diet rich in whole grains helps, and Malt-o-meal cream of wheat (also excellent for morning sickness!!!) has 100% of the RDA for adults in one serving. Mr Boy's favorite new food, Odwalla protein bars -- are they available on the East Coast? -- also serve as a yummy way to get your 100% RDA.
BTW, I think the March of Dimes has been trying to get the word out a lot longer than 10 years, I'm almost positive I read all about it when I was preggo with my first son, 15 years ago.