Status quo, as resumed by a blog post:
Currently, teens under 18 in Kentucky can marry at age 16 or 17 with a parent’s permission. Teens under 16 can marry with a judge’s permission in case of a pregnancy, though critics say if a girl under 16 is pregnant, it is evidence of a sex crime because she would have been too young to consent to a sexual relationship.
First of all, a pregnant woman should be able to marry the father of the child unless it would involve incest, adultery, sacrilege of vows of chastity (if the father is a priest or the pregnant woman a nun, since in the case a "marriage" would be invalid and involve further sacrileges beyond the one already done), or disparity of worship (if one is baptised and other is not baptised and won't get baptised).
Second, a sex crime can be amended by precisely culprit marrying victim if she so wants to.
Third, in Medieval Latin Christendom, a girl of Twelve was legally capable to marry, even without parental consent. She was also legally presumed capable of consent to fornication and adultery (which in Christendom were not punishable by death), except if she was a virgin, in which case the crime stuprum was a kind of equivalent to statutory rape, except it depended on her being virgin, not on her being 12. So, a widow of 12 and a half could legally consent to fornication. A virgin of 15 or 17 could not, but the culprit was free to make up by marrying the victim. Parental consent was customary except where already married and widowed or already sham married and annulled. It was not a legal requirement.
These are the rules that the Catholic Church upheld, these are the rules that should be upheld.
Making courts capable of forbidding marriage even with parental consent, as proposed by some legislators of Kentucky*, fulfils dire Biblical prophecy:
" Now the Spirit manifestly saith, that in the last times some shall depart from the faith, giving heed to spirits of error, and doctrines of devils,  Speaking lies in hypocrisy, and having their conscience seared,  Forbidding to marry, to abstain from meats, which God hath created to be received with thanksgiving by the faithful, and by them that have known the truth."
[1 Timothy 4:1-3]
Obviously, the "marriage at 18 and parental consent for no one" rule would involve some evil spirits coming some places earlier than others.
In 1870, it was imposed on Former Papal States, I suppose, as they were annected by the Kingdom of Italy. If not, Kingdom of Italy got involved in that game after offending Papacy. Either way, while Pius IX ruled in Rome and Romagna, including Nettuno, a twelve year old girl could certainly marry. By early 20th C. it was 18, as I read in Dummrath.
A bit later this evil change came to Russia, in the case of 18 in the Russian Revolution.
In this context, consider that while 616 is not the number of the beast, since it belongs to Nero rather than to Domitian**, it is still bad enough. How does this relate? Well, in Russian, both Vladimir and Ilich would have been very valid ways to refer to a certain Ulianov. He was quarter Swedish and in sweden his last name is spelled Uljanov. Now check IULJANOV. Even so, Czars had previous to that deviated from the Catholic standard.
This is a reason why Kentucky should not deviate from it further than they already did.
Hans Georg Lundahl
St Francesca of Rome
PS, as we today celebrate St Francesca, patron saint of Rome, widow, it may be noted that her marriage was at age ... 12. Probably with parental consent or even guidance, as she was pious, but it would not have been a legal requirement./HGL
* If I understand the blog post correctly, read it for yourselves:
Why Conservatives Objected to that Kentucky Child Marriage Bill
March 5, 2018 by Libby Anne
** How does 666 belong to Domitian? Well, if you take Latin vocative "Domitiane" and spell it DOMITIANE or French phrase "à Domitien" and spell it ADOMITIEN, you only need to add up ASCII values for each letter, there are no accented ones, especially not in the Latin vocative (French tend to omit accents in capitalisation, but this is optional), so the 26 standard letters go in upper case 65 for A to 90 for Z.