Relating to multiple possessions of multiple objects

Is it correct to say doctors specialties when referring to the (multiple) specialties of multiple doctors?

Solution 1:

Possessive plural would be doctors' specialties, meaning many doctors having specialties. It would be ambiguous whether each doctor had one specialty or more than one. One doctor having many specialties would be doctor's specialties. While I was writing this, MT_Head provided a nice link to the Chicago style manual that should help you out.

Solution 2:

You would write "doctors' specialties."

Here's the Chicago Manual of Style's free sample Q&A on multiple possessives: http://www.chicagomanualofstyle.org/CMS_FAQ/PossessivesandAttributives/PossessivesandAttributives08.html

Specifically, this phrase: "It’s always correct to form the plural possessive with an apostrophe"