There could be a few reasons why doctors marry other doctors. It could be because they share a common interest in medicine and want to stay close to one another. It could also be that they think it will help them make more effective decisions when it comes to their patients. In some cases, it could be because they think it will give them a greater sense of community. Whatever the reason, it's interesting to see doctors tie the knot with other doctors.
I once heard from our family doctor saying: Don't marry doctor as it is one of the profession who wouldn't spend much on his/her time at home. WHy? Because they are always on call when it comes to their duty and spend more time treating their patients. SO from that point of view coming from them, marrying their own co-doctors is ideal as there is a possibility that they can work with each other in the same hospital even if they are in diff. department.
Although some doctors marry nurses and/or their secretaries too.
In any relationship there should be understanding and care between the couple, when they both are from same career ,its easy to build up good relationship than the normal ones ,I think that might be a reason for the doctor marrying doctor.