There are companies that act as stem cell banks that will take your children's milk teeth in by post and process them and store them (hopefully where they will never be required).
They also process and store stem cells from umbilical cord/blood.
Google: stem cell bank
(I've kept most of my daughter's milk teeth just because that's where the "tooth fairy" dumps them after the requisite £1 or £2 has been extracted. I have no plans to actually send them to a stem cell bank though.)
Struggling to think of any reason you would want to store umbilical cord blood for your own child? Accidental exposure to a myeloablative dose of irradiation? Donating umbilical cord blood for others to use however is a very good idea.
Damage to an organ that requires transplant but not urgently? Better to have your own dna than someone else’s and have to take immunosuppressants forever.
There are companies that act as stem cell banks that will take your children's milk teeth in by post and process them and store them (hopefully where they will never be required).
They also process and store stem cells from umbilical cord/blood.
Google: stem cell bank
(I've kept most of my daughter's milk teeth just because that's where the "tooth fairy" dumps them after the requisite £1 or £2 has been extracted. I have no plans to actually send them to a stem cell bank though.)