e sexual impulse is very often associated with a
strong desire for offspring there can be no doubt, and in women the
longing for a child--that is to say, the longing to fulfill those
functions for which their bodies are constituted--may become so urgent and
imperative that we may regard it as scarcely less imperative than the
sexual impulse. But it is not the sexual impulse, though intimately
associated with it, and though it explains it. A reproductive instinct
might be found in parthenogenetic animals, but would be meaningless,
because useless, in organisms propagating by sexual union. A woman may not
want a lover, but may yet want a child. This merely means that her
maternal instincts have been aroused, while her sexual instincts are still
latent. A desire for reproduction, as soon as that desire becomes
instinctive, necessarily takes on the form of the sexual impulse, for
there is no other instinctive mechanism by which it can possibly express
itself. A "reproductive instinct," apart from the sexual instinct and
apart from the maternal instinct, cannot be admitted; it would be an
absurdity. Even in women in whom the maternal instincts are strong, it may
generally be observed that, although before a woman is in love, and also
during the later stages of her love, the conscious desire for a child may
be strong, during the time when sexual passion is at its highest the
thought of offspring, under normally happy conditions, tends to recede
into the background. Reproduction is the natural end and object of the
sexual instinct, but the statement that it is part of the contents of the
sexual impulse, or can in any way be used to define that impulse, must be
dismissed as altogether inacceptable. Indeed, although the term
"reproductive instinct" is frequently used, it is seldom used in a sense
that we need take seriously; it is vaguely employed as a euphemism by
those who wish to veil the facts of the sexual life; it is more precisely
employed mainly by those who are unconsciously dominated by a
superstitious repugnance to sex.

I now turn to a very much more serious and elaborate attempt to define the
constitution of the sexual impulse, that of Moll. He finds that it is made
up of two separate components, each of which may be looked upon as an
uncontrollable impulse.[19] One of these is that by which the tension of
the sexual organs is spasmodically relieved; this he calls the _impulse of
detumescence_,[20] and he regards it