The Rambam defines a zar in hilchos bi'as mikdash ch. 9:
ב איזה הוא זר: כל שאינו מזרע אהרון הזכרים--שנאמר "וערכו, בני אהרון" (ויקרא א,ח), "בני אהרון" ולא בנות אהרון.
The Minchas Chinuch on this week's parsha (390) quotes the safeik of the Parashas Derachim whether a woman kohenet has the status of a zar and is included in the prohibition of "v'zar lo yikrav aleichem". Is the exclusion of "bnei Aharon v'lo bnos Aharon" a giluy milsa that women are also defined as zarim or is it a seperate din, an issur aseh? From the defintion of zar which the Rambam offers -- all who are not male kohanim -- it does appear that woman are included in the lav.
R' Yosef Engel (Esvan D'Oraysa #19) points out that the gemara (Zevachim 15b) derives from "v'yinazru m'kodshe bnei Yisrael" that there is a seperate prohibition of performing avodah which defiles korbanos. Even if a woman is not included in the prohibition of zarus, because her avodah is invalid she would be in violation of this lav of defiling kodshim.