[punky]

I think it is partly due to the jurors not paying attention. Jurors often assume that because someone is up there with a PhD, decades of experience, that everything is said is fact. Whereas actually some of it is fact, and some is opinion. If they aren't paying attention you wouldn't realise the difference. Fact is fact, but with an opinion, and equally qualified doctor could quite easily testify to the opposite. Facts are pretty damning, ubt opinions, should just be offereed as another piece of evidence to be analysed next to all the others to see if it fits a pattern.