The cramping of love by institutions is one of the major evils of the world. Every person who allows himself to think that an adulterer must be wicked adds his stone to the prison in which the source of poetry and beauty and life is incarcerated by 'priests in black gowns'. Perhaps there is not, strictly speaking, any such thing as 'scientific' ethics. It is not the province of science to decide on the ends of life. Science can show that an ethic is unscientific, in the sense that it does not minister to any desired end.
Science also can show how to bring the interest of the individual into harmony with that of society.
We make laws against theft, in order that theft may become contrary to self-interest. We might, on the same ground, make laws to diminish the number of imbecile children born into the world.