Nowadays guys should be numb to immodest clothing. At my last church, there were teenagers who came with bare midriff, very short shorts, tight jeans, etc. Even among the older women, some of them showed a lot of cleavage especially the elderly ones. I don't think it is a big deal if a male ministers to a woman. Sure there is probably a few out of a thousand who may be tempted but most of the time it is fine. The women in church are not looking to seduce.