To be honest, I would not introduce drugs into my infant unless they where nesessary. For years now many people are growing up just fine with PKU with a good diet in place. I would just keep him eating green and let him make the choice later.
In the UK, we have not been told anything of this Kuvan drug. And from what im hearing, there seems to be a lot of miss guided use of it. Ive heard comments like take Kuvan and eat what you like.. fairly sure thats not correct… Its clearly states on their site (To be used with a low phe Diet) and to me that seems pointless if you are on your diet then your phe will be low anyway.. Of course it may help when sick, as that raises your phe levels regardless of diet issues.
To be honest i think its more of a hype, espicially as its the only drug the pharma companies have at the minute. The way i see it is if it was great, then every PKU pateint would be given it.