Is a deaconess a permissible church office?
i) Appeal is sometimes made to Phoebe in Rom 16:1, who has that designation. However, that's inconclusive inasmuch diakonos may not be a technical term for a church office in that passage.
ii) A better bet is 1 Tim 3:11. On balance, I think 1 Tim 3:11 refers to a deaconess rather a wife of a deacon. That's because it would be odd for Paul to stipulate the qualifications for the wife of a deacon but omit the qualifications for the wife of an elder. Since an elder is a higher office than deacon, surely it would be at least as important, if not more so, to give the qualifications for an elder's wife if wives were in view, than the qualifications for a deacon's wife. If the wife's character is significant in the lesser case, it would be all the more significant in the greater case.
Admittedly, that's not a terribly strong argument, but there are no strong arguments on either side of this exegetical question. It is, however, a stronger argument than the opposing arguments.
iii) However, that doesn't settle the issue. In fact, it has almost no bearing on the issue. That's because the NT doesn't give a job description for the diaconate. We don't know what NT deacons did. And it may have been flexible.
From our distance, the diaconate is a cipher. Christians in Pauline churches knew what deacons did, but we don't. It's something Paul could take for granted when writing to churches he planted or supervised. We lack that insider info.
So whether or not it's permissible for a woman to be a deaconess depends on the job description we write for that office. In the absence of a NT blueprint, the specifics must be supplied by the denomination or independent church. Just because we use a biblical title doesn't mean what we call that office maps onto the NT counterpart. And that's not something we can reconstruct in detail.
So it comes down to the question of what duties we assign to the diaconate, and if that's suitable to women. In the absence of specific Biblical warrant, what general principles in Scripture are germane to this issue?
iv) Acts 6 is commonly thought to mark the institution of the diaconate. Since, however, it doesn't use that designation, it's hard to say. Of course, the idea can present absent the word, but it would be circular to presume it's referring to the diaconate.
v) Ultimately, it's really not about the title but the job description. In some denominations, it's basically a visitation ministry. To my knowledge, deacons typically do things like bringing communion elements to shut-ins and nursing home residents, encouraging the sick or widows/widowers, taking their prayer requests, praying with them.
I think that sort of thing is perfectly permissible (even commendable) for Christian woman to do. Indeed, some Christian women do that anyway, whether or not they have a title. Diaconal ministry is not an exercise of authority.
vi) However, this is bound up with two additional issues. There's the question of whether a woman or layman is permitted to serve communion. In liturgical/high-church traditions, the communion elements must be consecrated to become the "true blood and body" of Christ. In addition, the priest must be a man. That whole framework buys into a framework of priestcraft which I reject.
However, even if we grant that rigmarole, a deacon can administer the consecrated communion elements. He can bring the communion wine and wafers to the sick, shut-ins, &c., so long as they were consecrated by a priest.
vii) A second issue is whether the diaconate is an ordained church office. Some proponents distinguish between ordination and commissioning. I think that's an evasive distinction without a difference.
Strictly speaking, ordination is extrascriptural. That's often inferred from the imposition of hands. However, the imposition of hands was a flexible gesture with varied significance. It could symbolize the impartation of a spiritual gift, special commissioning, &c. It's not a lifetime certificate.
I'm not saying ordination is contrary to Scripture, but we need to distinguish between biblical categories and ecclesiastical developments. Although these may be consistent with Scripture, they aren't a mandatory framework. I think ordination can be a useful quality control mechanism. But the permissibility or impermissibility of a deaconess should not be cast in such anachronistic terms one way or the other. That's an extrabiblical refinement.
viii) Finally, Warfield has an interesting article on the subject: