Steve Bainbridge has an interesting point on the subject; here's the conclusion:

If Bush nominates as a replacement for O'Connor someone with demonstrated specialized expertise in a field in which the other members of the court lack expertise, that nominee likely will end up with disproportionately large influence on court decisions within his/her field. If Bush picks a specialist, accordingly, the Senate would be well advised to go beyond the narrow question of whether the nominee is likely to vote to overturn Roe and also ask: What is the nominee likely to do in his/her field of expertise? Indeed, in the long run, that latter question may matter a lot more.