After a blog discussion with Andreas Köstenberger a few years back, he posted on the topic, 1 Timothy 2:12—Once More.
The discussion is broken into two parts. First, there is the argument from lexical evidence. Regarding this, Köstenberger writes,
At the heart of the book were the two chapters devoted to lexical and semantic analysis. In the former, the likelihood was suggested that “exercise authority” (Grk. authentein) carries a neutral or positive connotation, but owing to the scarcity of the term in ancient literature (the only NT occurrence is 1 Tim. 2:12; found only twice preceding the NT in extrabiblical literature) no firm conclusions could be reached on the basis of lexical study alone.Note that Köstenberger makes no assertion that there is any evidence for a "positive" connotation. He only says that "the liklihood was suggested." He does not attach his endorsement to this notion. I suggest that he knows there is none.
He then suggests that we cannot come to a firm conclusion on the basis of lexical data alone. However, here is an occurence of the word in the second century AD,
3 cent. AD) Hippolytus (d. AD 235) On the End of the World. De consummatione mundi, in Hippolyt’s kleinere exegetische und homiletische Schrften, ed. H. Achelis in De griechischen christlichen Schriftsteller, 1.2 (Leipzig: Himrichs, 1897), 239-309.
“Therefore, everyone will walk according to his won desire, and the children will lay hands upon their parents, a wife will hand over her own husband to death and a man his own wife to judgment as deserving to render account. Inhuman masters will authentein their servants and servants shall put on an unruly disposition toward their masters.”
I am omitting a couple of other occurences because they are found in reconstructed fragments, but neither of them have a positive connotation. There are many other occurences of cognates of the word authentein and some of these are very negative.
they must be silenced, since they are upsetting whole families by teaching for shameful gain what they ought not to teach.And, in fact, Köstenberger recognizes that Marshal comes to this conclusion.
But Köstenberger continues,
A case in point is I. H. Marshall. In his 1999 ICC commentary on the Pastorals, Marshall at the outset indicates his acceptance of the findings of my study by noting that it has “argued convincingly on the basis of a wide range of Gk. usage that the construction employed in this verse is one in which the writer expresses the same attitude (whether positive or negative) to both of the items joined together by oude.”Yet Marshall proceeds to opt for a negative connotation of both terms “teach” and “have authority,” because he says false teaching is implied in the reference to Adam and Eve in verse 14.
This, however, is hardly the case. More likely, Paul’s concern was with women being the victims of false teaching, not its perpetrators (see esp. 1 Tim. 5:14–15). Also, Marshall fails to adequately consider the above-mentioned point, that teaching is virtually always construed as a positive activity in the Pastorals and that it should therefore be construed positively also in 1 Timothy 2:12.Köstenberger does not support his statement that "this ... is hardly the case" and he ignores the fact that didaskein does occur with a negative connotation in Titus 1:11.
In conclusion, only one interpretation fits the facts - that of Marshall. Authentein is most likely a word with a negative connotation, and in this verse didaskein refers to some innapropriate teaching which women were involved in. It may very well be that the author of this epistle meant that women should not teach in a mixed group. I really cannot tell from this verse.
One thing is very clear to me. There is no evidence, lexical, semantic, grammatical or otherwise, which supports the notion that authentein could mean "pastoral leadership."