Not just "are the changes binding" but also "are the changes relevant". The changes might be binding for future services, but previous services were provided under the old terms; so you can make an argument that any arbitration clause in the new terms doesn't apply to services rendered before the new terms took effect.
Most terms of service include automatic acceptance of future changes, so if you continue to use the service the terms apply to the past too.
“23andMe may make changes to the Terms at any time. If we make a material change to the Terms, we will notify you, such as by posting a notice on our website or sending a message to the email address associated with your account. By continuing to access or use the Services, you agree to be bound by the revised Terms.”
