DEAR MISS MANNERS: Every year, my family spends a week at the beach with my in-laws. They pay for the beach house, which is something we can’t afford and for which I am always properly grateful. At the in-laws’ suggestion, my son and daughter each bring a friend on these trips.

Last year, they rented a house with only enough bedrooms for two of the four children to have a room. My son and his friend shared a room, and my daughter and her friend had to sleep in the hallway. It was no big deal; there’s not much difference in their ages, and there’s no reason why one would have more or less of a need for privacy.

My mother-in-law rented the same house for this year’s trip, and I assumed that my son would sleep in the hallway this time. However, she has announced her intention to assign him the bedroom again.

She has a rather Neanderthal habit of showing preference for males, treating the females in the family as second-class citizens. She will give my son an expensive skateboard for his birthday, for example, and then give my daughter a coloring book. It’s partly a generational thing. This is a woman who still calls flight attendants “stewardesses” and uses several other outdated terms.

Do I have any right to voice an opinion in this? On the one hand, she’s the host; on the other hand, it hurts my daughter’s feelings. The ongoing pattern of favoritism even makes my son uncomfortable at times.

GENTLE READER: No, you do not have the authority to reassign rooms in someone else’s house. Nor to reeducate your mother-in-law, however badly she needs this.

But you do have the authority to educate your children — in this case, by showing your son how to act on his feelings of discomfort.

He could ask his grandmother, “Would it be all right if I switched with Lily? She was in the hall last summer, and it doesn’t seem fair. Ethan and I would be happy to sleep in the hall.”

Please send your questions to Miss Manners at her website, www.missmanners.com; to her email, [email protected]; or through postal mail to Miss Manners, Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO 64106.