It was an interesting weekend for lads of draft age, judges, justices, lawyers and ordinary folks concerned about our defense posture.

There is disagreement about the registration that Congress ordered. The legal challenge to it was based on the contention of discrimination: men were being ordered to do something women didn't have to do.

The ruling that an all-male draft is discriminatory and therefore unconstitutional, and the subsequent decision of Justice William J. Brennan Jr. to stay the order, brought the Equal Rights Amendment back into the spotlight. ERA was the very question that was discussed in this space last week: Is it in the spirit of ERA to draft citizens for military service without regard to sex? Is that how the courts would interpret the amendment?

There is lively argument on that point, and on most aspects of ERA. But Washington Post readers seem unaninous on one thing, at least. They are agreed that I was wrong in saying what I did about ERA.

My mistake was in noting that serious questions have been raised about how ERA would be interpreted by the courts. Also, I said I could understand why doubters are wary about what lies ahead. Nevertheless, I repeated my support for ERA because women have not yet achieved equal rights.

This had the salubrious effect of uniting District Liners as few things have ever united them before. Those who oppose ERA wrote sarcastic letters about the dimwittedness of people like me who favor ERA; and those who favor ERA attcked me for admitting that there may be two sides to the question.

One of the few letters that confined itself to issues rather than to my lack of intelligence was from Bruce P. Kirk of La Plata. He pointed out that the proposed Equal Rights Amendment says, "Equality of rights under the law shall not be denied or abridged by the United States or by any State on account of sex." This, he observed, would not deal with all the inequities women suffer because biased individuals and business firms deal unfairly with them.

The proposed amendment would not, he said, go beyond the 14th Amendment that has been a part of our Constitution for 112 years. The 14th orders that no state shall make any law that abridges the privileges or immunities of citizens of the United States, nor shall any state deny to any person the equal protection of the laws.

Bruce found it "interesting to note that the great progress made toward racial equality, by law and by humanity," was made under the aegis of a constitutional amendment that makes no mention of race.

What I know about law you could put in your eye and feel no discomfort. However, it seems to me that the 14th Amendment does at least as much for women as ERA would, and possibly more. The 14th deals not only with rights but with privileges and immunities, and certainly those two areas of protection would be of value to women.

The privileges and immunities of women have been part of our social structure for thousands of years.

Among other things, we have not subjected women to involuntary military service, and for good reason.

If we ever change our minds about drafting women, I am sure the change will come only after prolonged debate that culminates in agreement on terms and conditions designed to protect the interests of women.

Regardless of what the Constitution says or refrains from saying, an expectant mother cannot perform the same physical duties an expectant father can. Two people can have equal worth, equal dignity, equal rights and equal status in the eyes of the law -- and stil be different.

The law ought to deal with those differences in a fair and equitable manner.

Pretending that there are no differences between men and women, or between the roles of men and women in our society, is of no help in spelling out civilized rules of conduct for both sexes. UPDATE

Last week, we took note of a Dr. Pepper "$100,000" Give-Away that offered $20,500 worth of prizes to those whose copies of an ad contained the right playing cards.

My copy contained a winner, the 10 of spades, and five acquaintances also had the 10 of spades. It seemed likely we had not won any of the money prizes, but rather a 50-cent-off coupon on a six-pack of Dr. Pepper.

Subsequently, a dozen readers reported they had also "won with the 10 of spades. But I am beginning to suspect that those of us who rushed off to the store to "save" 50 cents were losers, not winners.A few days later, Safeway ran a 70-cent-off coupon on Dr. Pepper.

Why doesn't Dr. Pepper just lower its list price and treat every customer equally? Why doesn't every vendor?