Ebenezer Henderson (1784 - 1858) was a minister in the Anglican church, and a highly accomplished linguist who understood perhaps twenty, or more languages. He spent two decades travelling and preaching in Eurasia, including several years—at the personal invitation of Czar Alexander I—spent exploring the vast Russian Empire, whilst supervising translations of the bible into numerous languages.
A year after his return to Britain in 1825, he published his book Biblical Researches and Travels in Russia, in which he described his time in Poland, and the Jews he meet there. Henderson states that due to the Jewish custom of marrying their children off at a very young age, Jewish men in Poland would regularly have sexual relationships with their pubescent, and pre-pubescent daughters-in-laws, whilst their sons—the husbands of the abused girls—were still children themselves.
Henderson termed this "incestuous familiarity", he knew that sexual relationships with daughters-in-law are strictly forbidden in all branches of Judaism by G-d's Torah (Leviticus 18:15). But Henderson didn't seem to be aware that Rabbinical Jews (90% of the Jews in the world today), made themselves a Talmudic loophole, which exempts a Jewish man from being technically guilty of 1. Adultery, 2. Incest, if they have intercourse with their daughter-in-law, whilst her husband (their son) is still a minor.
Henderson wrote of the Jews in Poland (full book here):
"They generally marry at thirteen and fourteen years of age, and the females still younger. I have heard of a rabbi, who was disposing of his household, preparatory to his departure for Palestine, that gave one of his daughters in marriage who had but just completed her ninth year. As a necessary consequence of this early marriage, it often happens that the young couple are unable to provide for themselves ; and, indeed, altogether incapable, from youth and inexperience, of managing the common concerns of domestic economy. They are, therefore, often obliged to take up their abode at first in the house of the husband's father, except he be in reduced circumstances, and the father of the bride be better able to support them. The young husband pursues the study of the Talmud, or endeavours to make his way in the world by the varied arts of petty traffic for which this people are so notorious. It is asserted to be no uncommon thing among the Jews, for a father to choose for his son's wife some young girl who may happen to be agreeable to himself, and with whom he may live on terms of incestuous familiarity during the period of his son's minority."
"Our Rabbis taught: [And the man that committeth adultery with another man's wife, even he that committeth adultery with his neighbour's (neighbour = Jew) wife the adulterer and the adulteress shall surely be put to death]. 'The man' excludes a minor; 'that committeth adultery with another man's wife' excludes the wife of a minor;"
— Babylonian Talmud, Sanhedrin 52b, Soncino Edition
GEMARA Our Rabbis taught. "'And the man' — to exclude a minor. 'Who commits adultery with another man's wife' — to exclude the wife of a minor. 'His neighbour's wife' — to exclude the wife of a non-Jew (lit. 'others'). 'They shall Surely be put to death — by strangulation.
TRANSLATION AND COMMENTARY
... The words, 'who commits adultery with another man's wife,' teach that a man is only liable for adultery if he had sexual intercourse with the wife of a grown man, to the exclusion of the wife of a minor, for marriage of a minor has no validity in Torah law. The words 'his neighbour's wife,' teach that a man is only liable for adultery if he had sexual intercourse with the wife of a fellow Jew, to the exclusion of the wife of a non-Jew who is not considered a 'neighbour,' for the marriage of a Jewess to a non-Jew has no Halachic validity.
HALAKHAH (Jewish Law)
... "If a man had intercourse with the wife of a minor, he is not liable, for the marriage of a minor has no validity." "
— Babylonian Talmud, Sanhedrin 52b, Steinsaltz Edition
SOURCE (winstonsmith's matchless blog)