Physiologists have given many absurd ideas on this subject, and almost all their theories have been exploded. In olden time it was believed that male children came from the right ovary of the mother, while females came from the left. Hence it was asserted that on whichever side she lay after connection, the ovary on that side would be impregnated. This plan of producing girls or boys at pleasure did not work, and was discarded even before the present minute knowledge of the principles of generation became known. The sex of an infant is not necessarily determined at its conception. In their unformed state, the Testes are within the body in about the same position as the Ovaries, and are similar to them in appearance. It is therefore possible that certain causes may influence the sex of the Foetus after it has commenced its growth. As a general rule, however, the sex of a child is influenced by circumstances at the moment of conception. Both experiment and observation have shown that the most ardent and vigorous individual of the couple, whether it be the man or the woman, will cause the sex of the child. On the other hand, where both are nearly alike in this respect, other influences must govern, and hence some couples have children of both sexes. The relative ages of married people frequently has an influence, because, when both are young, the oldest of the two is usually the most vigorous, and hence, as before stated, sex follows the predominating parent. Some physicians lay it down as a rule, that an elderly or middle-aged man will be sure to get boys from a young woman, and vice versa. But the rule does not work in every case. There is such a difference of sexual desires in different people, that it is impossible for any one, except perhaps themselves, to judge which has the most robust sexual powers. Another cause of sex is supposed to be the relative amorousness of the couple after impregnation has taken place. Some women experience much pleasure in sexual connection until they become enciente, and then all their desires suddenly cease. In cases like this, where the connection is continued, the husband would be apt to influence the sex after conception, and then the offspring would be male. But should circumstances prevent their continued connection, she would, in nine cases out of ten, give birth to a female child. To sum up, amorous females generally breed female children, while those of a colder temperament breed boys. When both are moderate in their desires, children of both sexes are produced. When the female is unnaturally amorous, (and such cases frequently occur,) she seldom becomes impregnated at all. The following mode of influencing the sex of the child, some physiologists assert, is really effective, and it looks reasonable. When the woman is just over her monthly turn—say within two or three days—the husband may then try for a girl. After one or two connections, let him abstain for the next month or two, or even longer. He thus impregnates his wife at the moment of her greatest sexual vigor, and by abstinence he does not influence the sex of the child after conception. Should he desire a boy, let him keep up his connection for two weeks or more after his wife has got over her monthly turn, at the same time carefully practicing the precaution of withdrawal, described in other pages under the head “Modes of Preventing Conception.” At that period the wife will have partially exhausted her amative powers, when he can be almost certain that a boy will be the result of her impregnation.

A curious fact relative to the resemblance of children to their parents has been developed by observation. Where a man is absent from his wife during the period of gestation, the child is almost sure to resemble the mother. On the other hand, an amorous father, who keeps a constant connection with his wife during pregnancy, will cause the child to resemble him. If a woman should become pregnant by one man, and then cohabit constantly with another during her pregnancy, the child would bear a resemblance to the second man rather than to its father. This would surely be the case if she were fond of the latter’s caresses.

It often happens that a married couple will have “a run” of children of one sex, and then turn round and breed those of the opposite sex. This may be accounted for by the failing health, and consequent vigor, of the predominating parent. Thus if a woman begins to breed boys, and after having had several, turns round and breeds a number of girls, it is a pretty sure sign that the sexual vigor of her husband is on the wane, or that his bodily health is failing. Should girls come first in rotation, and boys afterwards, the mother’s generative vigor may be suspected of falling off. These are, however, mere suggestive ideas; though readers may understand from them the principle upon which Nature forms the two sexes. I have no doubt that a careful and practical study of the subject may sometimes enable parents to elect the sex of their offspring, on the principle we have explained; but there are so many curious phases in the phenomena of procreation, that any certainty on the subject is out of the question.