o reason why the biological studies should not be
coeducational through nature-study and biology as far as the
development of frogs and birds and, in a general way, of mammals. In
fact, both of my textbooks, the "Applied Biology" and the "Introduction
to Biology," which emphasize reproduction of organisms more than other
high-school books, have been used throughout in coeducational classes.
However, these books stop where the problems of human life begin and
should be supplemented by lessons for sex-limited classes. There are
writers who suggest that segregation of the sexes for teaching
concerning human life may be at present a necessity because complete
frankness on sexual questions is certainly obstructed by tradition; but
we must not ignore the deep social reasons why, in general, there must
be maintained a certain amount of reserve between the sexes in the
consideration of some important problems of life. No educational theory
or practice can possibly alter the fundamental physical or psychical
relations of the sexes which nature seems to have fixed immutably.

[Sidenote: Married women as teachers.]

One other point that deserves attention in this connection is the
common statement that only married women, preferably mothers, can be
competent instructors of young women. This strikes me as more than
absurd. Personal experience is not always necessary for teaching in any
line. The greatest medical teachers have not had the diseases they
describe so clearly. The best elementary teachers and specialists on
the care of children are not always mothers; on the contrary, some of
these are men. The fact is that these teachers have learned, not from
personal experience, but from the great accumulations of scientific
knowledge of medicine, hygiene, and education. There is an abundance of
such knowledge relating to sex that may be clearly understood by bright
women who have no bi-personal knowledge of sex. Therefore, I believe
that it is nonsense to insist that only women with complete sexual
experiences can be efficient guides for other women.

Sec. 19. _The Child's First Teachers of Sex-knowledge_

[Sidenote: Mothers and other first teachers.]

The first instruction which may begin to lay the foundation for the
individual's sex-education should be given in early childhood by
parents, or by other adults, who happen to be on the most intimate
personal terms with the child. Usually this means the mother; but there
are nu