As you know PKU is a genetic disorder of amino acid metabolism. If you have made it to be 29 years of age and healthy enough to have kids, you surely have stuck to your recommended diet. The best type of physician to see for questions regarding genetic issues and pregnancy is a geneticist
or perhaps your partner's OBGYN. However, I can provide you with enough information that you will know what information you need to figure out your future kid's risk of PKU.
PKU is a recessive disorder. This means that you need 2 copies of the PKU gene to get the disease. Since you only have 2 copies, there is a 100% chance that you will pass down 1 copy of the gene. However, the chances of your kids actually having the disease (the chance of getting anther copy of the gene) depends on whether or not your partner has a copy of it. Assuming that your partner does not have PKU, then there is no way to tell if she has the gene until you get her tested. If she does have the gene, then there is a 50% chance that your child will have PKU. If she does not have the gene, then there is a 0% chance of your child getting the disease. I hope that made sense.
Since this disease has a fairly simple mode of inheritance, your primary care physician
can explain this inheritance scheme on paper if it would make it a little more clear. Good luck.