Can a woman conduct marriages?

Answer:

Marriages are not a function of the church. God established them when the world started (Genesis 2:24), long before Christ established the church.

Now, in a marriage ceremony, it is typical to teach a bit about what God says about marriage. This then runs into the command, "A woman must quietly receive instruction with entire submissiveness. But I do not allow a woman to teach or exercise authority over a man, but to remain quiet" (I Timothy 2:11-12). A woman cannot publically teach what God requires of a husband without teaching a man.

Marriage is also the administering of vows before God. This would be considered the exercising of authority, which is also forbidden.