Desperate US parents pay up to $20,000 a session for a procedure scientists say could be bogus Desperate US parents pay up to $20,000 a session for a procedure scientists say could be bogus Autistic children as young as 18 months old are being injected with human stem cells derived from umbilical cords in unapproved, unproven and potentially harmful “treatments” that scientists warn are proliferating across the US under the active encouragement of the US health secretary, Robert F Kennedy Jr .