"It's ingrained in us," says Dr. Lauren Feder, a Los Angeles physician who specializes in homeopathic medicine. "Many people around the world are lactose intolerant. We are the only animals [that], once weaned, ... drink another animal's milk. It sounds rather odd, but we have all grown up with that."

Dr. Feder, author of Natural Baby and Childcare (Hatherleigh Press, 2006), says parents should absolutely not give their children milk before they are 1 year old. She personally believes in giving her two children milk to drink in moderation.

Dr. Feder points out that 90 percent of food allergies are caused by dairy, egg whites, peanuts and tree nuts, shellfish and fish, soybeans and soybean products such as tofu and wheat.

June Cook, a mother from Carrollwood, Fla., says her son Adam, 7, is allergic to milk, but her son Eric, 4, can enjoy dairy without adverse side effects. She noticed problems when her older son started having frequent ear infections at the age of 2. "My pediatrician suspected milk allergy," Cook says. "We cut out the cow's milk and we had to be careful about what he ate." Cook, who breastfed for more than a year, went to an allergist and, through a skin test, found her son did indeed have a milk allergy.Alternatives to Cow's Milk

In lieu of breastmilk, Dr. Feder recommends goat's milk and non-dairy milks fortified with calcium. "You can take organic nuts like almonds and sesame seeds, which are the highest in calcium," she says. "Take a half cup organic nuts, grind the nuts to a fine powder in a blender and add a cup of cold water and sweeten as needed. The milk can be strained so it's the consistency of a normal milk."

Dr. Feder says people with a family history of milk allergies should be especially conservative about introducing dairy into a toddler's diet. She recommends waiting more than a year and introducing a little dairy at a time, starting with yogurt or butter. When buying dairy products, choose the organic versions whenever possible, she says.

Dr. Feder takes into consideration a family's culture and beliefs before recommending a particular diet. "Some families that are vegan are not going to go near an animal product like dairy," she says. "I happen to be married to a man from Switzerland, and that's the land of cows and cheese. I was not going to fight him on that. We use dairy as a complement but not the central part of a meal."Favorite Forbidden Foods

Dr. Rapp says if a toddler is allergic to milk, he or she must stay off all dairy products. "It will be their favorite food," she says. "If they don't get it they will cry and scream and holler. That's a good clue they have that problem. When you have a food allergy it's like an addiction."

In addition to noting whether your toddler has certain food preferences, Dr. Rapp also suggests keeping a diary. "I definitely feel you should keep a record of what is eaten, in particular an hour before you see a change in how your child acts or behaves," she says. "Milk will cause some children to have total changes in their personality within 15 to 45 minutes after they drink a glass of milk on an empty stomach."

She says a simple way to find out if your child has a milk allergy is to stop all milk and dairy products for a week. Then add it back on an empty stomach. "Within an hour you will see what it does," Dr. Rapp says. "Most food allergic reactions occur within an hour of the time you eat the food." Other signs of a milk allergy, which are delayed, include ear infections, asthma and bedwetting.

"Most toddlers will wet the bed anyhow, but as they get older, I found milk was a common cause of bedwetting in children over 5," Dr. Rapp says.

Dr. Rapp says some studies have linked milk to Sudden Infant Death Syndrome (SIDS), which is another reason to wait until after 1 year of age before introducing cow's milk to a child.

While most parents would not connect the "terrible twos" with a milk allergy, Dr. Rapp says a milk allergy can cause a toddler to have temper tantrums. As part of her research, she created a video in which she shows how putting a drop of milk under some children's tongues can cause them to become completely out of control.

When it comes to milk allergies, usually the problem is not isolated to one person in a family, according to Dr. Rapp. "It's never a milk problem in one individual," she says. "It's usually a milk problem in the entire family. One person might get hyperactive, and another gets tired and another wets the bed and another has asthma and another has hay fever and it's all milk." She says whey and casein are the two main components in cow's milk that cause problems.

Casein accounts for most of the protein in milk. Whey consists of two main allergenic proteins, alpha-lactalbumin and beta-lactagobulin. "Now there are a lot of chemicals in milk," Dr. Rapp says. "All milk problems are not related to allergy. You can have a lactose intolerance, which is characterized by diarrhea. You can easily figure that one out. If your toddler drinks regular milk he has diarrhea but if he eats lactase-treated milk in which the sugar lactose has been digested, then the child can tolerate the milk without any problem."Some people are adamantly opposed to the consumption of milk by all children. Robert Cohen, the director of the Dairy Education Board in Oradell, N.J., and author of Milk: A-Z(Argus Publishing, 2001), says most parents rarely if ever take note of their children's negative reactions to milk. He points out that a number of reports link milk consumption with colic, intestinal bleeding, asthma, chronic diarrhea, SIDS and other serious problems.

When it comes to toddlers and milk allergies, it's important to listen not as much to what your toddler is saying as to what his behavior is telling you. While your toddler may crave milk and love pizza loaded with cheese, his passion for dairy may be a symptom of an allergy. Keep a dairy diary so you can connect tantrums, stomachaches and other symptoms to his food intake.