Ethics aren't expensive.

Investors Chronicle, January, 2007

Ethical investing doesn't cost money, according to new research. David Hobson and Anne-Marie Anderson, of Lehigh University in Pennsylvania, estimate that portfolios that selected ethical stocks or avoided unethical ones did, on average, as well as the S&P 500 between 1991 and 2004.

However, this is due largely to portfolios being equally weighted, rather than weighted according to market capitalisation, which allows them to exploit the good performance of smaller stocks.