The Elements of Moral Science (1835, 1856 ed.)
Duties Which Arise from the Constitution of the Sexes
It has already been remarked that the very fact that our Creator has constituted us with a capacity for a particular form of happiness, and has provided means for the gratification of that desire, is in itself an intimation that he intended that this desire should be gratified. But, as our happiness is the design of this constitution, it is equally evident that he intended this desire to be gratified only in such manner as would conduce to this result; and that in estimating that result we must take into view the whole nature of man as a rational and accountable being, and not only man as an individual but man also as a society.
1. The subject upon which we now enter presents a striking illustration of the truth of these remarks. On the one hand, it is evident that the principle of sexual desire is a part of the constitution of man. That it was intended to be gratified is evident from the fact that without such gratification the race of man would immediately cease to exist. Again, if it were not placed under restrictions, that is, were promiscuous intercourse permitted, the race would perish from neglect of offspring and universal sterility. Thus universal celibacy and unlimited indulgence would both equally defeat the end of the Creator. It is, therefore, as evident that our Creator has imposed a limit to this desire as a part of our constitution, as that he has implanted within us the desire itself. It is the object of the law of chastity to explain and enforce this limit.
2. As it is manifestly the object of the Creator that the sexes should live together and form a society with each other in many respects dissimilar to every other society, producing new relations and imposing new obligations, the laws of this society need to be particularly explained. This is the law of marriage.
3. As the result of marriage is children, a new relation arises out of this connection, namely, the relation of parent and child. This imposes special obligations upon both parties, namely, the duties and rights of parents, and the duties and rights of children.
This class of duties will therefore be treated of in the following order: