I agree with koala, the intended parents (the officIal term) should be legally and morally reponsible from conception.
Too many cases go awry where the surrogate demands more money, changes her mind, lies about whose baby it is, won't terminate, wants to terminate .... It is a child conceived for the intended parents whether it's their gametes or not. The decision should rest with them and if they would terminate for abnormality, it should be part of a legally enforceable document that the surrogate agrees. If she doesn't, then she shouldn't be matched with that couple, and vice versa.
The IP's should absolutely be at least financially responsible for their son!!
Legally, the boy is the surrogate mothers, whether she wants it to be or not, and that is wrong, she has no legal recourse to them paying for his keep, and I guess if he went into care, it's upon her head.
Surrogacy can work, but seems intercultural, international is too complex.