When a child arrives, parents have one brief opportunity to collect stem cells...

https://wiki-spirit.win/index.php/Why_Bank_T-cells_and_Cord_Components_Before_You_Get_Sick%3F_A_Clinical_Perspective

When a child arrives, parents have one brief opportunity to collect stem cells from the umbilical cord. Cord blood provides hematopoietic stem cells (HSCs) for treating various blood disorders