Biblical precedent. And from the pen of Paul, of all people, - the same person who in a couple spots pens those verses (such as in 1 Corinthians 14) that some have latched onto as instruction for all places and time; from this same apostle we have casual references to women leaders (and teachers) that shows Paul will be no slave to patriarchal snobberies when it comes to spreading the gospel of Christ. If deaconesses or converts like Lydia or Priscilla can give needed instruction to other teachers such as Apollos then it’s pretty clear that the case against women in ministry positions of authority has fallen apart already even in the New Testament just where such exclusion was supposed to have found sanction. Okay - yeah - that last reference about Apollos is actually from Luke (in Acts 18) but Paul also greets the same couple approvingly in his correspondence. [But more to the point - and yes - straight from Paul, we learn that in Christ there is neither Jew nor Greek, slave nor free, male nor female. All those old categories we so want to fuss about are brushed aside. - see the end of Galatians 3] Jesus himself didn’t seem to have any problem hanging about in homes led / owned by women - think Mary and Martha. And if in those patriarchal times our apostles and leaders, right up to Christ himself was so free with his recognitions and companionship, it really did rankle the establishment.
But I suppose the main reason I believe that women can be preachers and pastors is because I’ve seen it happen. I’ve had the privilege of being part of a church pastored by various preachers some of whom were women. They’ve done it well … which puts the lie to those who say it can’t or shouldn’t be done.