In the tenth installment of her "Dangerous or Safe?" series, pediatrician Dr. Cara Natterson sets the record straight on diapers -- both disposable and reusable.

The people who oppose disposable diapers worry about their environmental impact:

• They account for an estimated 2% of the garbage generated in the U.S.
• Over time they accumulate in landfills.
• In order to make these diapers, toxins like dioxin are released into our environment.

Disposable diaper foes also suggest that they might harm a baby's health, suggesting that the super-absorbent polymers (called sodium polyacrylate) responsible for absorbing the water in urine and stool could pose a direct risk to the child.

• Sodium polyacrylate is used in the form of crystals.
• These crystals absorb 200-300 times their weight in water, turning into a gel in the process.
• Sodium polyacrylate was used in tampons until 1985, but reports linking it to toxic shock syndrome resulted in its removal.
• But tampons are inserted into the body and the sodium polyacrylate in diapers is not only not inside the body, it is three layers removed.
• The crystals that parents often find on their children's skin when taking off a wet diaper are not sodium polyacrylate but rather urate crystals, a normal byproduct of urine which has had the water removed -- the dehydrated urate forms pinkish-orange crystals.

Cloth diapers are a good alternative to disposable diapers, but:

• They aren't necessarily environmentally pristine as some of them have bleached cottons, so the environmental byproduct dioxin is still generated.
• They have their own health concerns, because when a baby wets or soils a cloth diaper, the urine or stool sits right next to the skin, increasing the chance of diaper rash (compared to disposable diapers) if the diaper isn't changed quickly.

What is the bottom line?

• From a health standpoint, there is very little difference between disposable and cloth diapers: Both are safe.
• The real issue here is one of environmental impact.
• Some diaper manufacturers have produced "hybrid" diapers that have a reusable exterior shell and a disposable core. The idea here is to reduce the burden on our landfills while maintaining the convenience of disposability.
• When choosing a diaper, chlorine-free products are probably better for the environment. But there are other manufacturing considerations way beyond the scope of this book.