Tracking the progress of students who attended the centre has not been a priority, although a study is now under way.
The centre has learned lessons from accelerating children too much. Professor Julian Stanley, the Johns Hopkins professor who founded the programme, used to be known as the man who got children to college early. Now in his 80s, Professor Stanley has changed his mind after seeing the negative effects of pushy parents. He now recommends 16 as the lowest age for full-time university education.
There are also doubts about the methods used to select students. As The TES reported last week, critics have challenged the use of scholastic aptitude test to identify high-ability children. According to The National Centre for Fair and Open Testing in the US, the test, used for college entry, was never designed to spot bright teenagers. It reinforces inequalities of educational opportunity and seems to discriminate against low-income and minority students, says Christina Perez, of the NCFOT. She calls it an excellent way to "measure family income".
The organisation also argues that the SAT and the talent searches that precede it make the testing epidemic - affecting younger and younger children - worse. This warning will have particular impact in the UK where concern is growing about the burden of tests.
The cost of the programme is beyond the reach of some. It costs $30 (pound;21) to register for the Johns Hopkins talent search - which goes to the centre. To take the SAT, administered by the non-profit-making Educational Testing Service, costs another $25.
The cost of the summer-school programme is more than $2,000. Less affluent students such as Joshua (above) depend on sponsorship. In 2001, more than $2 million was donated towards fees. Half of this came from the Goldman Sachs bank's charitable foundation. One hundred "Goldman Sachs scholars" attended last year.
The British academy will be looking for donations so disadvantaged pupils can take part. These will help to avoid accusations that the academy is simply offering a leg up to the already privileged.