Dear KG:

You wrote:
> I need to write a formal business letter to clients. This is a lesbian
> couple who were married and share the same last name. What should my
> greeting be?
>
> Dear Mrs. & Mrs. Smith;
>
> Help.
>
The best thing, of course, is to find out what they prefer. Sometimes an application or order form will make this clear. My experience has been that most lesbians prefer Ms., but the civil union/marriage issue is new. When in doubt, you can use their first names as in Ms. Carol and Ms. Angela Smith.

Although it does not specifically address homosexual couples, see our April 1999 newsletter at https://www.englishplus.com/news/news0499.htm for some ideas that may help.