Your newborn daughter doesn't seem to have an arch on her feet. Is this something to be concerned about?

In most cases, no. Infants generally are born with what appears to be flat feet because their baby fat hides the appearance of their arches.By the time children reach the ages of 3 to 4 years, they lose the vestige of this baby fat and their arches begin to show.

Children with flat feet can be reliably and easily diagnosed by the time they reach the age of 5 years.

There are three types of flat feet. Fixed, flexible and a type called tarsal coalition. These conditions each involve structural differences.

The two most common forms of the problem are flexible and fixed flat feet. They are generally diagnosed through simple observation.

It is likely that a child has fixed flat feet if there is no arch present when the child's big toe is gently hyperextended or when he or she stands on tiptoe.

Fixed flat feet are caused by inherited flattening of the bony architecture of the feet. In most cases, no treatment is needed.

If the test reveals an arch, the child usually has flexible flat feet. This condition is also inherited. It results from pronation, or rolling inward, of the subtalar joints, the joint below the ankle.

Flexible flat feet may cause leg fatigue or pain in young children. In older children, the condition can result in shin splints or ankle pain. But some children's arches may tighten on their own and never cause symptoms.

Although it is usually easy to diagnose these problems, treatment decisions for them can be complicated. The reason is that there is no predicting whose flat feet will eventually cause problems.

Further, there is no clear-cut scientific data as to whether orthotics - the customized arch supports worn in shoes - promote arch development or merely ease pain.

Orthotics usually are prescribed if the pronation is causing a child pain. If the youngster is not experiencing discomfort, parents generally have the option to choose orthotic treatment or not.

Many doctors prefer to prescribe the orthotics as a hedge against future problems because it cannot hurt and may help in the long run.

Tarsal coalition is the third and rarest form of flat feet. Unlike the other two forms of flat feet, this problem is not hereditary.

Tarsal coalition occurs when bony bridges fuse the foot bones, causing constant pronation. Pain usually becomes apparent during early childhood, depending on the bones that are fused.

Physicians commonly use X-rays to diagnose this disorder. Children affected by it may require corrective surgery.