It would be inconvenient, the opinion went, even if it were necessary, to forbid intercourse during pregnancy.[14] During recent years, nevertheless, there has been an increasingly strong tendency among obstetricians to speak decisively concerning intercourse during pregnancy, either by condemning it altogether or by enjoining great prudence.

It is highly probable that, in accordance with the classical experiments of Dareste on chicken embryos, shocks and disturbances to the human embryo may also produce injurious effects on growth.

The disturbance due to coitus in the early stages of pregnancy may thus tend to produce malformation.

When such conditions are found in the children of perfectly healthy, vigorous, and generally temperate parents who have indulged recklessly in coitus during the early stages of pregnancy it is possible that such coitus has acted on the embryo in the same way as shocks and intoxications are known to act on the embryo of lower organisms.

However this may be, it is quite certain that in predisposed women, coitus during pregnancy causes premature birth; it sometimes happens that labor pains begin a few minutes after the act.[15] The natural instinct of animals refuses to allow intercourse during pregnancy; the ritual observance of primitive peoples very frequently points in the same direction; the voice of medical science, so far as it speaks at all, is beginning to utter the same warning, and before long will probably be in a position to do so on the basis of more solid and coherent evidence.
Pinard, the greatest of authorities on puericulture, asserts that there must be complete cessation of sexual intercourse during the whole of pregnancy, and in his consulting room at the Clinique Baudelocque he has placed a large placard with an "Important Notice" to this effect.