It is sound Biblically, if being an alter boy (or alter server) is supposed to be sort of a pre-cursor to the vocation of the priesthood. Women are not supposed to be in pastoral positions in the church body. Woman are allowed to minister to other women, but not to men. To me, having girl alter servers is the first step to accepting women priests. Incrementalism, as practiced by the Fabian socialists. To me, it's part of the whole "goddess" movement.