"The sexual cycle averages 26 to 28 days (they tend to speak of it as 26 days, approximating it to the lunar cycle). For 21 or 22 days the individual is somer, sexually inactive, latent. On about the 18th day hormonal changes are initiated by the pituitary control and on the 22nd or 23rd day the individual enters kemmer, estrus. In this first phase of kemmer (Karh, secher) he remains completely androgynous. Gender, and potency, are not attained in isolation. A Gethenian in first-phase kemmer, if kept alone or with others not in kemmer, remains incapable of coitus. Yet the sexual impulse is tremendously strong in this phase, controlling the entire personality, subjecting all other drives to its imperative. When the individual finds a partner in kemmer, hormonal secretion is further stimulated (most importantly by touch--secretion? scent?) until in one partner either a male or female hormonal dominance is established. The genitals engorge or shrink accordingly, foreplay intensifies, and the partner, triggered by the change, takes on the other sexual role (? without exception? If there are exceptions, resulting in kemmer-partners of the same sex, they are so rare as to be ignored). This second phase of kemmer (Karh. thorharmen), the mutual process of establishing sexuality and potency, apparently occurs within a timespan of two to twenty hours. If one of the partners is already in full kemmer, the phase for the newer partner is liable to be quite short; if the two are entering kemmer together, it is likely to take longer. Normal individuals have no predisposition to either sexual role in kemmer; they do not know whether they will be the male or the female, and have no choice in the matter. (Otie Nim wrote that in the Orgoreyn region the use of hormone derivatives to establish a preferred sexuality is quite common; I haven't seen this done in rural Karhide.) Once the sex is determined it cannot change during the kemmer-period. The culminant phase of kemmer (Karh. thokemmer) lasts from two to five days, during which sexual drive and capacity are at maximum. It ends fairly abruptly, and if conception has not taken place, the individual returns to the somer phase within a few hours (note: Otie Nim thinks this "fourth phase" is the equivalent of the menstrual cycle) and the cycle begins anew. If the individual was in the female role and was impregnated, hormonal activity of course continues, and for the 8.4-month gestation period and the 6- to 8-month lactation period this individual remains female. The male sexual organs remain retracted (as they are in somer), the breasts enlarge somewhat, and the pelvic girdle widens. With the cessation of lactation the female reenters somer and becomes once more a perfect androgyne. No physiological habit is established, and the mother of several children may be the father of several more. Social"