There are some words which end with -tra or -tsta or -ta. They are either of Greek origin or medical terms. Some of them can be used for both genders.

o poeta	The poet(male)	a poeta	The poet(female)
o profeta	The profet(male)	a profeta	The profet(female)
o acrobata	The acrobat(male)	a acrobata	The acrobat(female)
o ecologista	The ecologist(male)	a ecologista	The ecologist(female)