SAN ANTONIO -- More soon-to-be parents have been using their newborn's cord blood, but how they're using it has been changing.

Cord blood is blood that remains in the placenta after a child is born, according to the Texas Blood Cord Bank. Cord blood contains a large amount of stem cells, which are used as an alternative to bone marrow, according to the Texas Blood Cord Bank.

New parents Diana Winters and Ryan O'Connell have decided to save their new daughter's cord blood at a private bank.

"It seemed like an insurance policy for our baby," Winters said. "Why not?"

(Winters is an employee of Post-Newsweek Stations, the owner of KSAT 12.)

Parents' decision to keep cord blood has hurt public blood banks, said Mary Beth Fisk, the executive director of the South Texas Blood Cord Bank, which is one of less than 25 public banks that accept donated blood cells for use on the national registry of marrow donors. Private cord banks store blood for use by immediate family only.

"We certainly see cord blood donations or banking as a personal decision a family has to make," Fisk said.

One doctor said donating cord blood rather than banking is beneficial to everybody.

"Your child's cord may save someone else's life," said Michael Grimley with the Texas Transplant Institute. "Once you freeze a product, no one knows how long it's viable."

Grimley also said he is concerned if cord blood being used for a transplant is more than 10 years old, but O'Connell said the pros far outweigh the cons.

"Blood of your own family, as opposed to a public bank, seems like a good idea," O'Connell said.

Winters and O'Connell's daughter, Molly Isabelle, was born healthy, but her parents said they were willing to take the risk and costs of banking cord blood because cancer runs in their families. A private cord blood bank costs about $2,000 for an initial storage fee with an additional yearly cost of about $150.