Many people are (correctly) concerned about the grooming of children for sex. Let's look at what some religious traditions have to say.
Judaism (Maimonedes, The Book of Women, Sefer Nashim; Treatise 1 on Marriage, Ishut; Chapter 3)
If a girl is older than three years and one day, she can be consecrated [to marriage] through sexual relations with her father's consent. Should she be below this age, if her father has her consecrated through sexual relations, the marriage bond is not established. (For until the age of three, the relations are not considered sexual in nature (this by no means insinuates that they are insignificant or potentially harmful, only that they are not sexual)).
The Baal HaTosafot, a leading medieval Talmudic commentary,
wrote that the local community of the 14th-15th century simply did away with this prohibition and returned to betrothing their underage daughters (that is, under the age of 12). The Tosafot justifies this by saying simply, “hagalut hitgaber aleinu” — the exile has overwhelmed us.
Ashkenazis married off children very young. Among the Haredi, arranged marriages are common:
A ketannah (literally meaning "little [one]") was any girl between the age of 3 years and that of 12 years plus one day;[4] a ketannah was completely subject to her father's authority, and her father could arrange a marriage for her without her agreement.[4] If the father was dead or missing, the brothers of the ketannah, collectively, had the right to arrange a marriage for her, as had her mother,[4] although in these situations a ketannah would always have the right to annul her marriage even if it was the first....Unlike divorce, mi'un was regarded with distaste by many rabbinic writers,[5] even in the Talmud;[10] in earlier classical Judaism, one major faction - the House of Shammai - argued that such annulment rights only existed during the betrothal period (erusin) and not once the actual marriage (nissu'in) had begun.
Islam
Ibn Qudamah (may Allah have mercy on him) said: “If a man gives his virgin daughter in marriage to someone who is compatible, then the marriage is valid. … With regard to a virgin who is a minor, there is no difference of scholarly opinion concerning that.
Ibn al-Mundhir said: All the scholars from whom we acquired knowledge are unanimously agreed that it is permissible for a father to give his minor daughter in marriage, provided that he offer her in marriage to someone who is compatible, even if she objects and refuses. The fact that it is permissible to give a minor girl in marriage is indicated by the verse in which Allah, may He be exalted, says (interpretation of the meaning): “And those of your women as have passed the age of monthly courses, for them the ‘Iddah (prescribed period), if you have doubts (about their periods), is three months, and for those who have no courses ((i.e. they are still immature)…” [at-Talaq 65:4]. So the ‘iddah for one who has not started to menstruate is three months, and the ‘iddah of three months can only be required in the case of talaq (divorce) or annulment of marriage. This indicates that (the girl who is a minor) may be married and divorced, and her consent is not essential.
‘Aishah (may Allah be pleased with her) said: The Prophet (blessings and peace of Allah be upon him) married me when I was six years old and consummated the marriage with me when I was nine. Agreed upon. It is known that at that age she would not be one of those whose permission would be taken into account. al-Athram narrated that Qudamah ibn Maz’un married the daughter of az-Zubayr when she began to menstruate, and something was said to him. He said: If I die, the daughter of az-Zubayr will inherit from me, and if I live, she will be my wife. And ‘Ali gave his daughter Umm Kulthum in marriage when she was a minor to ‘Umar ibn al-Khattab (may Allah be pleased with him).” (Al-Mughni, 7/30)
Hinduism
Every year, thousands of young girls between the age of five and ten are dedicated to Goddess Yellamma. When a devadasi was interviewed by the Wall Street Journal, “it was observed that a girl is married to the Goddess between the ages of ten and thirteen and the next phase of a girl begins during her first menses.”
Bhimappa was not yet 10 years old when she became a “devadasi” — girls coerced by their parents into an elaborate wedding ritual with a Hindu deity, many of whom are then forced into illegal prostitution.
Devadasis are expected to live a life of religious devotion, forbidden from marrying other mortals, and forced at puberty to sacrifice their virginity to an older man, in return for money or gifts.
“In my case, it was my mother’s brother,” Bhimappa, now in her late 40s, told AFP.
What followed was years of sexual slavery, earning money for her family through encounters with other men in the name of serving the goddess.
Attempts to reduce child marriage in India have stalled.
Buddhism
According to Brahmanical law a girl had to be married of within months of her first menstruation, after which her father would incur more blame the longer he delayed the marriage. The early Buddhists considered 16 to be a suitable marriageable age (patta soëasa vassa kàle, pattavaya, Ja.I,421). It was thought good for couple to be the same age (tulyavaya), although the Kàma Såtra (4th cent CE) recommends that the bride be three years younger than the groom. The Buddha thought it inappropriate and foolish for old men to marry women much younger than themselves (Sn.110).
Christianity
Canon 1083 currently sets the age of marriage as 16 years of age for boys and 14 years of age for girls. This maintains the ages set in the 1917 Code of Canon Law, Canon 1067. But, the 1917 code was a change from the pre-1917 code, which set the canonical ages of marriage at twelve for both ages (younger marriage was possible if the spouse had entered puberty). And for most of the Church's history, one could be betrothed to marriage by the age of seven, although younger betrothals were not uncommon.
1880 United States
Every state in the union set age of consent at either 10 or 12 years of age, with the exception of Delaware, which set it at 7 years of age. Some locales permitted it at the age of 9. In 1974, the age of consent in Florida was still 11 years old.
[As of 2023], although advocates have succeeded in getting seven states to ban child marriage with no exceptions, forty-three states still allow marriage under the age of eighteen, and seven states have no minimum age requirement for marriage so long as there is a parental or judicial waiver. Until recently, Wyoming fell into this category, but enacted a law in February 2023 to raise the minimum marriage age to 16 with most minors having to go before a judge for approval. ... In California, which has no minimum legal marriage age, a 2017 bill to ban the practice was defeated after advocates—including the American Civil Liberties Union (ACLU)—lobbied against it.