When Mark Tangarone wanted to teach his class Mandarin, he raised money for a set of dictionaries. To help his students understand economics, he created a fake currency and helped them bet on the stock market.
Last summer, however, despite Mr Tangarone's passion for teaching, he took early retirement after a row with his Connecticut school principal. The cause of the battle? Mr Tangarone wanted to teach his gifted eight to 10- year-olds about the work of Charles Darwin, showing pictures of his trip to the Galapagos Islands. But his principal forbade him for fear of controversy.
"I had to check that it was 2010 not 1910," the 55-year-old said, "and that I was living in southern Connecticut, not southern Alabama."
Ever since the famous Scopes "Monkey" trial of 1925, the American Religious Right has fought the teaching of evolution in schools. And since 1968, the Supreme Court has ruled as unconstitutional any attempts to replace evolution with the pseudo-scientific "alternatives" of creationism and intelligent design.
The religious lobby continues to launch fresh assaults but American courts consistently find in favour of science.
The US has no compulsory national curriculum, and only loosely enforced state standards, so if an individual school faces pressure from disgruntled parents it has enough autonomy to buckle.
Teachers and their managers know their own communities and it makes them risk-averse, according to Glenn Branch, deputy director of the National Centre for Science Education, a non-profit organisation that defends the teaching of evolution.
"All it takes is for a single student to complain and the administrators will lean on a teacher to tone down or even stop teaching evolution altogether," he said.
Michael Berkman and Eric Plutzer, of Pennsylvania State University, who recently carried out a survey on the teaching of evolution, advocate better training to help teachers tackle the subject with confidence and to defend their positions if challenged.
But this is of little help to Mr Tangarone. "I felt a little like Darwin must have - being attacked for what I thought were sound educational ideas," he said.
EVOLUTION IN CLASS
A national survey of 926 high school biology teachers in the US - published in the journal Science - found that only 28 per cent teach evolution with unequivocal support, while 13 per cent "explicitly advocate" creationism or intelligent design.
Of most concern to the report's authors - Michael Berkman and Eric Plutzer of Pennsylvania State University - are the other "cautious 60 per cent" who fail to take a strong position either way. They downplay the importance of natural selection, teach it at the micro-level but not in relation to humans, advise students to make up their own minds, or inaccurately present evolution as a scientific controversy.
"In their strategies of avoidance and comparisons with religious beliefs they are undermining the legitimacy of science and the power of scientific enquiry," Professor Berkman said. For a quarter of high school students, biology is the only science class they will ever take.