From elsewhere in The Post: The grandmother of 2-year-old twins, a boy and a girl, worries that their behavior is out of control.

“They have meltdowns at dinnertime, especially when guests are present — even when these guests are children, too — and they resist their parents a lot, particularly at nap times and mealtimes.

These children seem to feed off each other and become quite playful and silly, and then they push each other, cry and create general chaos,” she says in a letter to advice columnist Marguerite Kelly.

Kelly advises her to watch her grandchildren’s diet, because a lack of protein and low blood sugar can lead to fussiness, and suggests the twins’ parents hire a stern sitter to watch them when company is over.

To combat the twins’ tendency to feed off each other, Kelly says separating them may be the answer.

“A little distance should help, too, whether or not company is coming. If the parents separate the twins for a little while each day, they won’t rev each other up so much.”

How have you handled the terrible twos in your family? What can parents of multiples do when their kids like to misbehave together?