holding that male co-worker's comments and jokes in plaintiff's presence were not sufficiently severe or pervasive to establish an objectively hostile work environment

holding Feres doctrine applicable in medical malpractice suit against military physicians deriving from an injury sustained while training for the Olympics; "[C]ourts have often concluded military personnel acted `incident to service' and applied the Feres bar in cases arising from service members taking advantage of recreational military activities or other military perquisites because their use of the facilities was a consequence solely of their status as members of the military."

noting that in that case, most of the comments were not directed at plaintiff, a fact which contributed to the conclusion that the conduct was not severe enough to create an objectively hostile environment