In all likelihood, DNA evidence won't have much bearing in the Strauss-Kahn case. DNA evidence can prove that physical contact of one sort or another took place, but it can't prove whether or not that contact constitutes assault. Strauss-Kahn's defense will be that whatever took place was consensual, not assault. If his lawyers can convince the jury that no crime took place, it doesn't matter how much DNA he left behind.

The only way I can see that DNA evidence would carry much incriminating value would be if she had his skin cells under her nails from attempting to fend him off and he had corresponding scratches on his body. Even then, the scratches would have to be on his face or other place where scratching wouldn't normally occur during consensual sex. Scratches on his back would only serve to prove his point, not hers.