But even in the very conception of twins, which certainly occurs at
the same moment in the case of both, it often happens that the one is
conceived a male, and the other a female. I know two of different sexes
who are twins. Both of them are alive, and in the flower of their age;
and though they resemble each other in body, as far as difference of
sex will permit, still they are very different in the whole scope and
purpose of their lives (consideration being had of those differences
which necessarily exist between the lives of males and females),--the
one holding the office of a count, and being almost constantly away
from home with the army in foreign service, the other never leaving
her country's soil, or her native district. Still more,--and this is
more incredible, if the destinies of the stars are to be believed in,
though it is not wonderful if we consider the wills of men, and the
free gifts of God,--he is married; she is a sacred virgin: he has
begotten a numerous offspring; she has never even married. But is not
the virtue of the horoscope very great? I think I have said enough
to show the absurdity of that. But, say those astrologers, whatever
be the virtue of the horoscope in other respects, it is certainly of
significance with respect to birth. But why not also with respect to
conception, which takes place undoubtedly with one act of copulation?
And, indeed, so great is the force of nature, that after a woman has
once conceived, she ceases to be liable to conception. Or were they,
perhaps, changed at birth, either he into a male, or she into a female,
because of the difference in their horoscopes? But, whilst it is not
altogether absurd to say that certain sidereal influences have some
power to cause differences in bodies alone,--as, for instance, we see
that the seasons of the year come round by the approaching and receding
of the sun, and that certain kinds of things are increased in size or
diminished by the waxings and wanings of the moon, such as sea-urchins,
oysters, and the wonderful tides of the ocean,--it does not follow that
the _wills of men_ are to be made subject to the position of the stars.
The astrologers, however, when they wish to bind our actions also to
the constellations, only set us on investigating whether, even in
these bodies, the changes may not be attributable to some other than a
sidereal cause. For what is there which more intimately concerns a body
than its sex? And yet, under the same position of the stars, twins of
different sexes may be conceived. Wherefore, what greater absurdity can
be affirmed or believed than that the position of the stars, which was
the same for both of them at the time of conception, could not cause
that the one child should not have been of a different sex from her
brother, with whom she had a common constellation, whilst the position
of the stars which existed at the hour of their birth could cause that
she should be separated from him by the great distance between marriage
and holy virginity?