First, thanks to Rudi's legal research for directing me to this, the key point being that Maine allows single-sex boxing teams, but doesn't say for which sex.
Seeing the section in its entirety, however, what strikes me more is the following: is there really such a huge demand for (let's face it, it really is clear which sex gets the boxing team) women's boxing that (3) isn't sufficient?
C. Single-Sex Teams
An educational institution may sponsor single-sex team in interscholastic or inter-collegiate athletics competitions in the following instances:
(1) The institution sponsors a team for each sex in the same sport.
(2) The sport is boxing.
(3) The educational institution establishes one team in a sport and, as a result of athletic competition for places on the team, or the lack of interest of students, only the members of one sex become members of the team.