"Kemmer is not always played by pairs. Pairing seems to be the commonest custom, but in the kemmerhouses of towns and cities, groups may form and intercourse take place promiscuously among the males and females of the group. The furthest extreme from this practice is the custom of vowing kemmering (Karh. oskyommer), which is to all intents and purposes monogamous marriage. It has no legal status, but socially and ethically is an ancient and vigorous institution. The whole structure of the Karhidish Clan-Hearths and Domains is indubitably based upon the institution of monogamous marriage. I am not sure of divorce rules in general; here in Osnoriner there is divorce, but no remarriage after either divorce or the partner's death: one can only vow kemmering once. Descent of course is reckoned, all over Gethen, from the mother, the "parent in the flesh" (Karh. amha). Incest is permitted, with various restrictions, between siblings, even the full siblings of a vowed-kemmering pair. Siblings are not however allowed to vow kemmering, nor keep kemmering after the birth of a child to one of the pair. Incest between generations is strictly forbidden (In Karhide/Orgoreyn; but is said to be permitted among the tribesmen of Perunter, the Antarctic Continent. This may be slander.). What else have I learned for certain? That seems to sum it up. There is one feature of this anomalous arrangement that might have adaptive value. Since coitus takes place only during the period of fertility, the chance of conception is high, as with all mammals that have an estrous cycle. In harsh conditions where infant mortality is great, a race survival value may be indicated. At present neither infant mortality nor the birthrate runs high in the civilized areas of Gethen. Tinibossol estimates a population of not over 100 million on the Three Continents, and considers it to have been stable for at least a millennium. Ritual and ethical absention and the use of contraceptive drugs seem to have played the major part in maintaining this stability. There are aspects of ambisexuality that we have only glimpsed or guessed at, and which we may never grasp entirely. The kemmer phenomenon fascinates all of us Investigators, of course. It fascinates us, but it rules the Gethenians, dominates them. The structure of their societies, the management of their industry, agriculture, commerce, the size of their settlements, the subjects of their stories, everything is shaped to fit the somer-kemmer cycle. Everybody has his holiday once a month; no one, whatever his position, is obliged or forced to work when in kemmer. No one is barred from the kemmerhouse, however poor or strange. Everything gives way before the recurring torment and festivity of passion. This is easy for us to understand. What is very hard for us to understand is that, four-fifths of the time, these people are not sexually motivated at all. Room is made for sex, plenty of room; but a room, as it were, apart. The society of Gethen, in its daily functioning and in its continuity, is without sex. Consider:"