In the past the age was 12 in most of the world, the most surprising exception being Delaware where it was only age 7:
The first recorded age of consent law dates more than 800 years ago: in 1275, in England, as part of the rape law, a statute, Westminster 1, made it a misdemeanor to "ravish" a "maiden within age," whether with or without her consent. The phrase "within age" was interpreted by jurist Sir Edward Coke as meaning the age of marriage, which at the time was 12 years of age.
A small group of Italian and German states which introduced an age of consent in the 16th century also set it at 12 years. Toward the end of the 18th century, other European nations also began to enact age of consent laws. The French Napoleonic Code established an age of consent of 11 years in 1791, which was raised to 13 years in 1863. Nations such as Portugal, Spain, Denmark and the Swiss cantons, initially set the age of consent at 10–12 years and then raised it to between 13 and 16 years in the second half of the 19th century.
In the United States, by the 1880s, most states set the age of consent at ten or twelve, and in one state, Delaware, the age of consent was only seven. Women reformers and advocates of social purity initiated a campaign in 1885 to petition legislators to raise the legal age of consent to at least sixteen, with ultimate goal to raise the age to eighteen; the campaign was successful: by 1920, almost all states had raised the age of consent to sixteen or eighteen.http://en.wikipedia.org/wiki/Age_of_consentToday the tendency is to age 14. Around 1900 the tendency was 16 or 18 but that was found to be to high, and almost universally ignored by the Police and the Courts (Teenagers should not have sex, but they do and the Police and Courts have to pick up the pieces when it happens and things go bad). Do to the inability of the Police and Courts to STOP teenage sex, the movement since WWII has been to drop the age of consent to 14.
Here is a map of age of consent, but be careful if using it. For example it shows Pennsylvania age of consent as 16, that is true except of the people having sex are within four year of age of each other, then it is 14. In the late 1990s, the State of Pennsylvania had a case where it had to decide what was the age of consent to enter a common law marriage. The State Legislature had never addressed the issue thus what the law was had to be determined by the Pennsylvania Supreme Court, which ruled it was age 12. Subsequently it was changed to 18 by the State Legislature. Given that decision other states that recognize Common law Marriage, the law may be age 12 for most state legislature have NOT addressed the issue of Common Law Marriages in any form, while such marriages are still legal in those states.
Now the United Arab Emirates is reported to have the age of consent of 18, but it is a federation and as such it is up to each Emirate NOT the federation to make that decision. Thus I suspect the report is wrong. On the other hand, having sex outside of marriage is still a crime in the UAE and thus the sentence.
Side note: The UAE are Emirates run by Sunni Moslem ruling families over majority Shiite Moslem Populations. Among Shiites it is legal within their religion to form Temporary marriages for as short a time as needed to have sex. Most Prostitutes in the Persian Gulf and Pakistan call themselves Shiites for this reason. The prostitutes enter a "Temporary Marriage" for the transaction and then are "divorce" when it is over. Thus the sex is sex within marriage and thus legal (after one of his victories against other arabs Mohammad let his followers to enter into such temporary marriages, the Shiites said that was Mohammad's showing his approval of such temporary marriages, the Sunni said it was a one time act that was NOT meant to occur again. It is one of the disputes between Shiites and Sunnis. I bring it up for the problem may be that the parties in this action were non-Moslem more then anything else.