Xtauh have a strong tendency toward polyandry - the pairing of one female with multiple males. The number of males cohabiting with a female generally correlates with social status, often beyond what is practical for either reproductive needs or sexual satisfaction; this is usually due to social factors such as a desire for childcarers, or a display of wealth and status, or even to artificially restrict the supply of males (at least of a certain quality) available to other females.

Although the ratio of males to females hovers around two-to-one, it is not uncommon for lower-status females to fail to attract a male until they have established themselves to a minimum standard - to have some territory or property that they can assert in the face of other females. Even in this case, such a female often only has one mate, defaulting to monogamy. In some cases, multiple females may “share” one or more males between them; the reason for doing so may be economic (neither female might be able to support a male on her own) or simply due to a shortage of males, but the practice is almost always encountered when the females in question have a deep, familial-style bond, and most often when they are closely related and of the same age (sisters or first cousins). While the unbalanced gender ratio and sex roles of xtauh makes maintaining most of these alternative mating systems difficult on a large scale (except for polygynandry), scattered examples of each do exist, though polyandry generally remains the norm at the highest status levels.

Despite the above description, it is worth noting that in terms of purely sexual behavior, extra-pair copulation and promiscuity is not uncommon in both sexes. In most cultures, it is neither socially expected for married or otherwise bonded females to practice sexual fidelity, nor is it particularly notable should they fail to do so. The same is not true of married or bonded males, but despite prejudices against a husband cheating on one's wife, it happens more often than society is comfortable with, though the existence of male bands leaves males an option for a well-supported and marriage-free life from the beginning.

Xtauh mate after the fashion of most Earthly mammals, particularly lions, with the male mounting the female from behind. Mating is not restricted to a particular time or season, and is generally a voluntary choice, influenced as much by personal or social factors as much as a drive to produce offspring.

A peculiarity of xtauh reproduction is that mating, while necessary for conception, does not necessarily result in it, and not necessarily right away if it does. A mated female may fertilize her eggs immediately, but may also store sperm for up to four turns for future usage. This adaptation dates to the species' evolutionary history in the Brightness, where it serves as an insurance measure against harsh or unpredictable conditions. A female may therefore mate with multiple males over an extended period of time and produce a clutch of eggs only from one of them - or, indeed, more than one.

The above process is strongly influenced, but not controlled, by the conscious decision of the female; that is to say that a female may make a purposeful effort to conceive or not at a particular time and with a particular male's sperm, but that success is not guaranteed and may depend on other factors. A female in a state of malnourishment, or under significant physiological stress, or in an environment she perceives as hostile or inimical is generally less likely to conceive even if an effort is made, while an effort not to conceive is likely to be more effective; the opposite is true if the female is well-fed, healthy, relaxed, or in a safe and fruitful environment.

Once the female, whether intending to or not, releases sperm to fertilize her eggs and conception occurs, the process is largely beyond her control; the development of her offspring will proceed until finished or interrupted.

The precise number of eggs fertilized and laid is beyond the female's direct control, and is affected both by the female's own personal biochemistry and by factors similar to those governing the chances of conception (fewer eggs if the female is stressed, underfed, in harsh environments, etc). The vast majority of natural reproductive events result in between one or two eggs, which spend an average of a turn and two vigils after conception developing within the female's body (even in healthy gestation, this may vary by several vigils in either direction). The eggs are approximately round (only slightly oblate) and are between 21 and 23 cm in diameter and 5 and 6.6 kg in mass, with a slightly yellowish shell.

The eggs will hatch after approximately two and two-sixths turns of incubation. During this period they must be kept in an environment that is warm without being hot (preferably 25 to 30 degrees Celsius) and not too dry (at least 50% relative humidity). For this reason, xtauh nests tend to be dug out of the ground down to a level that will provide insulation and moisture, with the eggs surrounded with a small amount of decaying vegetation and then loosely buried.

Mating, though somewhat more frequent during the Waning period of a turn, depends on the preferences of the participants; combined with the possible delays between mating and conception, this means that it is not possible to talk of mating or laying seasons among xtauh, though many nomadic peoples prefer to lay their eggs somewhat before sunset, so that their earliest days are not exposed to excessive daytime heat. The same factors render it impossible to speak of an even loosely set breeding interval, to say nothing of the social elements that are also involved.

The physiological effort and the investment of energy and nutrients involved in producing, carrying, and laying eggs depletes a female's body in a way that, however quickly she may appear to recover, takes time to replenish. While the number of different factors involved - diet, age, health, social stress and conflict, environmental conditions, even the number of previous pregnancies – make it difficult to pinpoint a breeding interval that is “safe”, provided conditions are optimal, once to twice per cycle is relatively nonthreatening. That said, whether or not reproduction is good for her health may not be the primary motive for any given female, and there are very often pressures to produce children more often.

One is the simple fact of mortality, particularly infant mortality; food supplies are not always optimal, and xtauh knowledge of medicine, hygiene and biology are crude at best. Children being among the most vulnerable segments of the population, it is not at all unusual for them to die before reaching maturity, if indeed they hatch at all; a mother will often want to replace those that were lost, and to ensure that many children are produced to ensure that at least some survive. Another is status: fertility is, in most xtauh societies, taken as both a privilege and a duty; a gift of divine favor and superiority, to be used to advance one's bloodline and one's people. High-status females, in particular, are generally expected to bear many children, and are lowered in the sight of their peers if they do not.