You can get sued in any specialty.The most sued specialties are surgical the least,as reflected in lower premiums are peds,psych,neurology,derm,physical/rehab medicine.General FP (without OB) and IM have fairly low malpractice rates in most states which are risk adjusted.Pathology also has below average malpractice risk and premiums.
My guess would have been that peds are sued more often than other primary care physicians. Just a guess. Don't forget, however, that peds can be sued for some crazy time period after seeing the kid. My understanding is that they can be held liable until the patient is either 18 or 21 years. Imagine seeing a well baby at the 1 year check-up at the end of your carreer (lets say age 65.) You could potentially be called to defend yourself at the age of 85. Kind-a-sucks.