Bernstein last week, Daniel Wynn, a multiple sclerosis investigator, said that most patients being evaluated for safety were not given spinal taps--the most conclusive test for PML and the virus that causes it.

FORBES: Tysabri Still Down, But Not Out

And how conclusive does gene test data have to be before allowing it to go on a drug's label?

FORBES: Genetic Testing

Their findings may not be entirely conclusive because they did not test immigrant children who had not started puberty early for pesticides.

BBC: Premature puberty link to DDT