AE 40:3914: But in the congregations or churches where there is a ministry women are to be silent and not preach [I Tim. 2:12]. Otherwise they may pray, sing, praise, and say “Amen,” and read at home, teach each other, exhort, comfort, and interpret the Scriptures as best they can.
http://www.angelfire.com/ny4/djw/lutherantheology.womenpastors.html
Gerhard on 1 Tim. 2:12: The meaning is: “I do not allow a woman to teach publicly in the church, but privately she may teach those of her household. I do not forbid this even among those of hers who are male if she is better instructed in the faith (Acts 18:26). But on this occasion she should not arrogate to herself authority over a man.”
Petersen: All of this needs to be noted for the Office of the Ministry is limited by God to males and we have feminized it without even knowing it. We are not told in Scripture exactly why God limits the Office to males, but it is surely related to the fact that God in the Flesh chose to be born of a woman as a male, He gives Himself masculine pronouns throughout Scripture, and ultimately He reveals Himself to us with the masculine names: Father and Son. The Church is Herself feminine, of course, but the Office that represents Christ and stands in His stead, and serves His Bride on His behalf, is markedly and exclusively male.