"Things you put in your body will, you know, affect the growth and development of your baby's brain, of their bones, their whole body system, so I guess you think about that for your younger kids, too," said Seubert.
"Some studies have linked even low-level mercury exposure in pregnant women and young children to subtle impairments in hearing, hand-eye coordination and learning ability," said Dr. John Santa, director of the health ratings center for Consumer Reports.
Consumer Reports tested two types of tuna at an outside lab -- both albacore and light tuna -- 42 samples in all.
"Every sample of tuna we tested had measurable levels of mercury. The tests confirm that for some people, such as pregnant women and children, they still need to limit the amount of tuna they eat," said Kim Kleman, Consumer Reports editor-in-chief.
How much tuna is too much? One serving is about 2 to 2.5 ounces.
"With albacore tuna, if a pregnant woman ate one serving of any of the samples we tested, she would exceed the daily mercury intake that the Environmental Protection Agency considers safe," said Kleman.
And with about half the light-tuna samples, eating about two servings would exceed the government limit.
"Our food-safety experts recommend that pregnant women, as a precaution, should avoid canned tuna altogether," said Kleman.
And children under 45 pounds shouldn't eat more than 1.5 ounces of albacore tuna a week, or about 4 ounces of light tuna, provided no other mercury-containing seafood is eaten.
But tuna is not the only fish in the sea. Clams, Alaskan salmon, shrimp and tilapia are consistently low in mercury, a good choice for most anyone to eat.