Cord blood banking is one of the many decisions you’ll make while you anticipate the arrival of your baby. And it’s often not an easy decision to make. So, we’re breaking it down to help you make the best decision for your family.

7 frequently asked questions about umbilical cord blood banking

1. What is cord blood banking?

The blood in a baby’s umbilical cord contains blood stem cells, which can grow up to be almost any kind of blood or immune cell they’re coaxed to be. These stem cells can be banked at the time of your baby’s birth, and later used to treat conditions such as leukemia, anemia, sickle cell anemia and other rare diseases.

You may have seen brochures in your doctor’s or midwife’s office about the value of storing your baby’s stem cells. If your child or their sibling develops a rare disease or some other condition with few treatment options, cord blood in the freezer may come to the rescue.

But just how useful those cells might be for one of your children is hard to predict, and cord-blood banking companies often overstate the possibilities. It’s true that thousands of stem cell transplants have treated blood, immune and metabolic diseases since the late 1980s, but it is important to remember that there are only a handful of diseases that they are able to treat—at least right now.

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2. What do stem cells do?

Until the discovery of cord blood stem cells, the only transplants that could treat conditions such as leukemia were bone marrow transplants, which carry a higher risk of blood-borne infections or the body’s immune system rejecting the transplant.

Stem cells offer a less risky alternative, but only for children. There aren’t enough cells in cord blood for an adult, and there are enough only for one transplant.

The process of stem cells “growing up” also takes longer after one of these transplants, which means there’s a longer window of possibility for infection.

3. So if my child has leukemia, their stem cells might help them?

Not necessarily. If your child’s immune cells couldn’t fight the leukemia already, more of the same cells are unlikely to help. Similarly, stem cells can’t help much if your child has a genetic disorder, because their stem cells have the same genes—that being said, research is under way to see if this could change in the future.

Stem cells are more likely to help siblings, but that’s only if the blood matches—a 25% chance.

4. What other conditions can stem cell transplants treat?

Currently, stem cells can successfully treat five types of conditions in people: blood cancers, bone marrow failure, genetic blood disorders, immunodeficiencies and genetic metabolic disorders. (Here’s a complete list of the conditions, most of which are fairly rare.)

It’s hard to estimate both the likelihood of these diseases afflicting your child or a family member and the likelihood that cord blood can help them, but estimates range from 1 in 1,000 to 1 in 200,000. The most accepted number is about 1 in 2,700.

Clinical trials are testing how helpful cord blood might be for all sorts of conditions, from diabetes to cerebral palsy to neurological and autoimmune disorders. Promising results on treating deafness, arthritis, Parkinson’s and liver cirrhosis have been found in studies in rats; it’s hard to say if it will translate to humans in the future.

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5. How much does cord blood banking cost?

Like most insurance policies, cord blood banking is a gamble—and not a cheap one. Banks charge between $2,000 and $4,500 to store the blood for up to 21 years, usually requiring a yearly maintenance fee of $100 to $300 on top of that.

Donating your blood, which we’ll discuss in a moment, is free.

6. So, should I bank my baby’s cord blood?

I wish there was an easy answer to give you here.

If you know of a family medical history involving a condition that’s treatable with stem cell transplants, banked cord blood could be a lifesaver later on for a sibling or other family member.

The heartwarming success stories that companies describe are real, and people have definitely benefited from banked cord blood. Plus, technological advances may discover other remarkable uses for cord blood.

It’s just that the odds are pretty low that you’ll need them, and other treatments may come along in the meantime.

If you go with a commercial bank, research carefully how well the blood is stored and, if available, what FDA inspections have revealed about them.

It is important to note that at American Academy of Pediatrics (AAP) has some concerns regarding private cord blood banking. Banks are not FDA regulated, and the stem cells that are banked there are used less often than the one in public banks (more on that below). Your best bet is to speak with your medical team to see what their recommendations for your specific scenario are.

7. Can I donate my baby’s stem cells?

Yes! If you decide commercial cord banking isn’t right for your family, you can also donate it to a public cord blood bank for research or treatments for other people. Donating is free and is strongly supported by the AAP.

Unfortunately, you may not be able to get it back if you need it later. However, if you know ahead of time that someone in the family may need it for a condition treatable with stem cells, you can make a “directed donation” that reserves it for that person’s use only (nontransferable and also offered by private banks).

A version of this story was originally published on Nov. 26, 2019. It has been updated.