No Best Man, But A Best Woman Instead — Is This Wrong?

My niece has been best friends with a male since they were in middle school. They have never dated nor have they ever been romantically involved, but have always been very close friends.

He is engaged to be married to a woman he met while at college. He has male friends who will be in the wedding party, but he considers my niece to be his best friend, and has asked her to be his "best man," or in this case "best woman." The bride is fine with the idea. My niece will be standing up with the bride's sister who will serve as the maid of honor. But the groom's parents think this is completely wrong.

They feel it will be very awkward, embarrassing, and may ruin what could be a nice, traditional wedding. They have asked my niece to say "no" to this idea. While talking about this on the FUN 107 Morning Show today, we had a call from Kristen telling us that she was a "grooms-woman" in the recent wedding of a male friend of hers, and it was great.

Should she turn down the request, or go ahead and do what the groom has asked of her. What do you think?