I know tribes have been discovered in which people did not know where babies come from, but it comes as a surprise to learn many Americans do not know where apples come from.

A celebrated art (paintings) critic and a noted fashion (female garments) critic recently told me they were surprised to hear that if you plant a seed of an 'Albemarle Pippin' apple you will get an apple that may be utterly different from the apple that bore the seed.

Good grief. Is sex really such an esoteric subject in our country that grown people are startled by it?

Of course, there is nothing wrong with ignorance; we are all ignorant of most things that might be learned about. It's just that most people, I had assumed, knew that sex involved contributions from two individuals, and knew this from an early age.

Since that is a false assumption, I shall speak today of sex in apples and other plants, which operates very much as sex in humans does. It will be discovered (since it has not been noticed, evidently) that a human child is not identical to either of its parents. Furthermore, if there are five children, say, they will vary from each other, sometimes very greatly.

That is because at the time of conception half the chromosomes (on which are lined up the genes) come from one parent and half from the other. The whole point of sex is to prevent filling the world with people exactly like ourselves, and surely this is one of the most comforting thoughts in all of science.

If one parent has blue eyes and the other parent brown, the child has an equal chance to have either blue or brown eyes. Except that some inherited physical qualities are dominant, when passed on, while others are recessive. Brown eyes are dominant, blue are recessive. If the brown-eyed parent comes from a long line of brown eyes, the baby will have brown eyes. But if the brown-eyed parent's father, say, had blue eyes, the recessive gene for blue may be present and may combine with a gene for blue eyes in the next generation, thus producing a blue-eyed baby even when one parent has brown eyes.

In any case, sex works the same in apples. Apples are fruits (babies) produced as a result of sexual activity and the fertilizing of an egg by a sperm. If a thousand seeds are sown and raised from an 'Albemarle Pippin,' you will get a range of physical characters in the resulting trees (and their fruit) from individuals very similar to one parent to those which are similar to the other parent. And in between, apples not like either parent but different from both.

Sex is not utterly simple. You may get surprises. You will not always get, from any cross (sexual mating) a range of individuals covering the whole possible spectrum of variation. Some of the inherited genes may be dominant, thus swamping (in the first generation) the recessive genes contributed by the other parent. Some genes may not work together. And there is such a thing as dosage factors, in which a gene is more or less dominant but subject to influence from other genes.

Those unfamiliar with sex at all may then inquire how it happens you can get a tree, generation after generation, that always produces 'Albemarle Pippin' or 'Granny Smith' or some other particular apple. The answer is simple, these trees bypass sex, and are produced by grafting the tissue of a particular apple on the understock of something else. Never mind the understock, for the moment; the point is that the tree grows from tissue of the desired variety of apple, with no contribution from the outside. There has been no sex.

As if we were to produce babies from our fingernails or hair or a bit of skin from our arm. Then the baby would be exactly like ourselves. An apple produced from tissue of the apple -- from its hair and nails, so to speak -- will produce the identical apple.

If, however, you grow an apple from seed, you are getting into sex. You do not have merely the original tissue, but a seed produced from two parents, just as we produce human babies. And whenever you do this, you are getting two -- not one -- donors of inheritance, and the offspring will thus not be identical with either parent.

Someone has asked how certain apples are not bred (by sexual crossing of two different apple trees) but just discovered. This changes nothing. An apple seed may sprout and grow in a woodland, and like an apple grown from a seed anywhere else, it will be a new kind of apple, the result of inherited physical qualities from its two parents. It may be superior to both of them, and this may be noticed and apple growers may wish to grow it. They simply graft the desirable apple (though found in the woods) on understocks and thus perpetuate the identical apple indefinitely. It is exactly the same as if the apple were deliberately bred and raised in a nursery for the production of new varieties.

As long as an apple is produced sexually (and not simply grafted from the tissue of one tree) it will be different from other apples. It may be less desirable than its parents, or equally desirable, or far more desirable. If it is outstandingly different and better, it will probably be noticed and propagated by grafting from then on out. An outstanding apple may be discovered in a breeder's nursery, or a woods, or a pasture, or in an amateur's back yard, since any apple from seed will vary from its parents, and may be better, just as it may be worse.

Another source of new apples is the sporting of some existing variety. On one tree of 'Delicious' apples you may find all the apples are the usual color, shape, texture, flavor and so forth, except on one twig you may discover an apple somewhat different from all the others. It may have a slightly different color, or shape, or the flesh may have a slightly different aroma or texture. If you think it's a nice change, you can graft tissue from that variant twig to an understock and wind up with apples just like the variation you discovered on the one particular twig. Again, sex has been bypassed, there has merely been a change in the original tissue.

When two parents are used to produce offspring, the progeny will vary from both. Some plants, especially wild plants, have existed for so long that variation is only very slight. (Some animals, too. If you breed a Jersey cow and bull you will get a Jersey calf nearly identical with its parents). Thus if you sow dandelion seeds, you will find the new dandelions much like their parents. Same with regal lilies and many other plants.

If, however, the plants have been produced through hybridization, using quite different parents, you will get wide variations in the offspring. Regal lilies produce regal lilies just like themselves, with very little variation, because (I speak only of the wild plants) no new outside lines of genes have been introduced into the parentage.

Tall bearded irises, however, may vary enormously, because a number of quite different species of irises have been bred together in the past, and today's progeny may acquire genes not from just one wild species (like the regal lily) but from a number of species, all quite different with quite different genes to pass along.

The more mixed up the parentage is, the wider the variety you may expect in the offspring. The closer the breeding has been (in the wild or in cultivation, it makes no difference, as long as new genes are kept out of the line through not using new parents of different genetic makeup) the less variation you will find.

Except for occasional and rare instances of sports, all new varieties of apples or people or anything else come from sexual blending of two different parents, hence the mongrel nature of all humans and of most garden flowers. Sex is, however, somewhat more complicated than it seems on the surface. Many have noticed this.