HOUSTON -

"I'm a big sushi fan. So I've always wanted sushi," said Patty Holmes, a new mother and member of the Houston Sushi Club. She added, "But it's such a challenge, because when you're pregnant there are all these things they tell you not to have."

Holmes just gave birth to her son David Christian. When she was pregnant her cravings for sushi were hard to resist. But Holmes knew raw sushi was a no-no.

"Mostly cooked fish obviously. That's the safest way to go," said Holmes.

But that conventional wisdom is now being questioned by another mother. Her name is Emily Oster and she wrote a controversial book called, "Expecting Better: Why the Conventional Pregnancy Wisdom Is Wrong-and What You Really Need to Know."

In it, Oster says three sins of pregnancy, raw sushi, wine and coffee shouldn't be off limits.

"I think on the coffee, the evidence suggests certainty in moderation, 200 milligrams a day. That's probably two little cups, said Oster. She added, "Most women should feel comfortable having sushi from a reputable source. The same kind of sushi you would have when you're not pregnant."

And what about wine?

"On alcohol this has clearly hit a nerve," said Oster. She added, "Alcohol no more than two drinks a week in the first trimester and no more than one drink a day in later trimesters."

Here's the catch, the author, Emily Oster, is a mom, but she isn't a doctor.

Oster is an economist. She's an Associate Professor of Economics at the University of Chicago.

"My job is really about analyzing data and figuring out what it can tell us," said Oster.

WJXT's sister station in Houston, KPRC, spoke with a doctor for her take on the controversy and the big cravings during pregnancy. Dr. Cristina Perez, an OB/GYN with The Women's Specialists of Houston at Texas Children's Pavilion for Women, broke down what she says is really safe for expectant moms and what they should definitely avoid.

"There are some studies that have been done with extreme amounts of coffee that have shown an increased risk for miscarriage and so we feel drinking coffee in moderation, about a cup is a safe amount," said Perez.

When it comes to alcohol Perez said, "I think that we'll never be able to study how much alcohol is safe in pregnancy, because they won't do a study testing which babies end up having fetal alcohol syndrome."

And finally, sushi.

Perez says it's okay just be sure to avoid fish high in mercury and make sure your sushi is cooked.

"But with raw sushi we recommend that pregnant women avoid because there is an increased risk for food borne illness," said Perez.

The Houston Sushi Club and Kubo's Sushi Bar & Grill say the safest sushi dishes while pregnant are a California roll without the fish eggs, Tamagoyaki which is a cooked egg omelet, cooked eel or smoked salmon. You could also go for a rock and roll, which is fried shrimp or a vegetarian roll.

So being pregnant doesn't mean you have to eliminate all your favorite foods, just be conservative.

"Pregnancy is not a good time to try the latest, hottest, Japanese food trend," said Holmes. She added, "Wait until you're done having kids to go and try those."

To see a list of the Houston Sushi Club's pregnancy safe sushi dishes go to houston-sushi.com/sushiformoms.html.