All three children are shown to have inherited the intelligence of John Paul and his wife Theresa, though there are hints throughout the Shadow series that they may have also been genetically enhanced.-- Wikipedia article about Ender's father
(hat/tip: DavRob60's answer to "Is Ender genetically-engineered? ")
The only genetic engineering that I recall being mentioned in the Shadow series was Anton (who was implied to have never done any practical work) and Volescu's experiment on Delphiki embryos, whose only surviving result was Bean. Neither had anything to do with John Wieczorek or Theresa Brown/Wiggin.
Is the Wiki wrong, or am I simply failing to remember some other hints I may have missed?
UPDATE: Never let it be said that SFF doesn't improve the Internet! That erroneous (as I was suspecting) statement was just edited out of Wikipedia!
19:20, 5 October 2013 Jeepday . . (3,469 bytes) (-129) . . (Remove statement that is speculative, unreferenced, and to the best of my knowledge untrue.)