The higher the evolution of the creatures, the more is the parental responsibility shared by both parents. Among human beings the institution of monogamy, which is universally accepted as a higher form of human relation than polygamy, involves in the dual partnership a certain sharing of the actual physical difficulties of parenthood by the father which is not entailed in the fatherhood of a polygamous establishment. In fact, a pure monogamy strictly maintained, does really affect the physical aspects of expectant fatherhood _more_ than it does the physical aspects of expectant motherhood. The modern pair, being intensely and deeply united, the effects of the experiences and physical states of one have actual reverberations and physical effects on the other. In this respect the change in the girl’s attitude of mind towards the man, which is sometimes a result of the physical effect of motherhood (see Chapter III), may have a very far reaching influence upon the man’s health and happiness if he does not comprehend the cause of this experience, and, through comprehension, know how to endure or overcome it. Undoubtedly a home which is disturbed by uncomprehended antagonisms or suppressed irritations has a physical effect on the general mental balance, and consequently on the whole health of the pair involved. The way in which these difficulties can be overcome is by a mutual comprehension, so far as is possible, of the needs of each other, and sometimes perhaps by the attitude of “bowing before the storm” until it has passed, recognizing that it is a phenomenon beyond human control. Beyond this may be subtler and more intricate reverberations from his wife’s state. The actual physical fact has to be faced by the father-to-be that perhaps rapidly following on the period when all his natural desires for a completed sex union with his wife were met and consummated by equal desires in her, there comes a time when such impulses on his part are not only not responded to by his wife, but are perhaps antagonized and may be entirely thwarted by either her mental or her physical condition. In Chapter XII, I will show how, to some extent, and at probably rather long intervals, his impulses may be not only satisfied but may be harmoniously responded to and may be profoundly valuable. Nevertheless, in almost every period of coming fatherhood, there will be at least some months when bodily union is actively repugnant and consequently actively harmful, to the wife. At such a time the instinctive feeling of the mother against any act should be sufficient to bar it, because, even if the act itself should not be harmful, to force her will at such a time or to lure her into coercing herself against her own will is in itself harmful. A young husband, therefore, will be faced by periods in which it will be impossible for him to have any of the unions to which he may have become accustomed and which his natural virility may at first continue to demand.