Section 5: A marriage is incestuous and void whether the relatives are legitimate or illegitimate between either:1. An ancestor and a descendant;2. A brother and sister of either the whole or the half blood;3. An uncle and niece or an aunt or nephew.If a marriage prohibited by the foregoing provisions of this section be solemnized it shall be void, and the parties thereto shall each be fined not less than fifty nor more than one hundred dollars and may, in the discretion of the court in addition to said fine, be imprisoned for a term not exceeding six months. Any person who shall knowingly and wilfully solemnize such marriage, or procure or aid in the solemnization of the same, shall be deemed guilty of a misdemeanor and shall be fined or imprisoned in like manner.
"Does section 5 (3) of New York's Domestic Relations Law void as incestuous a marriage between an uncle and niece 'of the half blood' (that is, where the husband is the half-brother of the wife's mother)?"
I also conclude that the apparent purpose of section 5 (3) supports a reading that excludes half-uncle/half-niece marriages from its scope. Section 5 as a whole may be thought of as serving two purposes: it reflects long-held and deeply-rooted values, and it is also concerned with preventing genetic diseases and defects. Sections 5 (1) and 5 (2), prohibiting primarily parent-child and brother-sister marriages, are grounded in the almost universal horror with which such marriages are viewed - a horror perhaps attributable to the destructive effect on normal family life that would follow if people viewed their parents, children, brothers and sisters as potential sexual partners. As the Appellate Division explained in Matter of May (280 App Div 647, 649 [3d Dept 1952], aff'd 305 NY 486 ), these relationships are "so incestuous in degree as to have been regarded with abhorrence since time immemorial."
The second purpose of section 5's prohibition of incest is to prevent the increased risk of genetic disorders generally believed to result from "inbreeding." (It may be no coincidence that the broadening of the incest statute in 1893 was roughly contemporaneous with the development of the modern science of genetics in the late 19th century.) We are not geneticists, and the record and the briefs in this case do not contain any scientific analysis; but neither party disputes the intuitively correct-seeming conclusion that the genetic risk in a half-uncle, half-niece relationship is half what it would be if the parties were related by the full blood. Indeed, both parties acknowledged at oral argument that the risk in a half-uncle/half-niece marriage is comparable to the risk in a marriage of first cousins. First cousins are allowed to marry in New York, and I conclude that it was not the Legislature's purpose to avert the similar, relatively small, genetic risk inherent in relationships like this one.