IT'S A GOOD THING the White House has sent Mrs. Reagan along with the president to the summit. If she weren't there having tea with Mrs. Gorbachev, taking a boat ride with a group of children and visiting a drug treatment center, half of all Americans wouldn't bother to follow what's going on in Geneva at all. It's women, of course; they simply can't comprehend what the issues are or what's at stake. We know this because Donald Regan, the White House chief of staff, told us so. Poll your readers, he said; they'll agree.

It seems that women, according to Mr. Regan, don't "understand throw-weights or what is happening in Afghanistan, or what is happening in human rights." They'd rather read "the human interest stuff." That probably explains why the British haven't been included in the conference. How could the prime minister even follow the debate? She'd probably be sneaking away to listen to an alpenhorn concert just when the going got rough on SDI.

To be fair, Mr. Regan did backtrack a mite in giving this assessment to the press, conceding on second thought that "some women will (understand)." But we'd be willing to bet that this modification came after he noticed any of the following immediate reactions from those who heard his initial opinion: 1)jaws dropped and he was asked to repeat his statement; 2)the reporter began to smile and scribble furiously; 3)he caught a muttered expletive from the aide who was going to have to explain, defend or disavow the remark later.

Mr. Regan should stop worrying. Women are clever. They've mastered vacuum cleaners and washing machines, and some can even figure out the family phone bills. It shouldn't take long for them to catch up on technically difficult questions such as human rights or the military conquest of a smaller, weaker nation. As for Tridents, Pershings, cruise missiles and SS-25s, others have been able to absorb this information even to the point of being able to hold an opinion. It is said that Mr. Regan himself, not previously known as a weapons expert, received intensive tutoring in preparation for the summit meeting, coaching so thorough that he was known in some circles as the Eliza Doolittle of arms control. If he can learn, surely there's hope for a few women.