In 1885, there was a furore in London after investigative journalist William Thomas Stead brought attention to child prostitution in London. His methods may have left something to be desired, however:
Through a middle man, W. Stead purchased 13 year old Eliza Armstrong from her mother for the sum of £5, had a midwife confirm she was a virgin, and then had her brought to an actual brothel and drugged. He arranged for himself to be the customer, and having reportedly drunk a whole bottle of champagne to play the part, he took Eliza to a room and waited for her to wake up. When she did wake up, next to Mr. Stead, she screamed, whereupon William quickly left the room. In the aftermath, he arranged for the Salvation Army to take care of Eliza, who was taken to France to the care of a Salvationist family.
William Stead used these events as material for his newspaper article series, The Maiden Tribute of Modern Babylon, which was an instant hit and spread like wildfire. Public opinion quickly pressured the Parliament to issue the Criminal Law Amendment Act 1885, or "An Act to make further provision for the Protection of Women and Girls, the suppression of brothels, and other purposes". Among other things, it raised the age of consent from 13 to 16. The article series also inspired female reformers in the US to petition for legislation raising the age of consent from 10-12 (which was common in most states) to 16, and ultimately to 18. And this was done in almost all the states by 1920.
As for William Stead himself, he was made to stand trial for the Eliza Armstrong affair, and sentenced to three months imprisonment. He lived until 1912, when he was one of the victims of the Titanic.
Eliza Armstrong was eventually brought back from France, after the prosecutor at Stead's trial raised the funds to place her at a training centre for girls to become servants. Where she went from there is unknown.
It would seem that we owe much of our sexual morality to this investigative journalist of intrepid if dubious character. It was headed in a more progressive direction anyway, but "The Maiden Tribute of Modern Babylon" seems to have been quite the catalyst. Now people called for more severe punishments for sexual offences, and they seem to have been made especially aware of the vulnerability of children with regards to sexual offence as well as the vice and, well, vices of prostitution. In light of this, however, I do wonder if these articles, along with their societal ramifications, might also not have helped shape the mentality behind the motives of the murders three years later. Not as the only factor, of course, but in part, at least?
Oddly, I've just been reading on Stead. His story "The Mail Steamer went Down" is featured in one of the back issues of "Ripperologist", and deals with a passenger ship sinking with insufficient lifeboats, which cause would eventually prove Stead's own doom on the Titanic.
He's got his own appreciation website at http://www.attackingthedevil.co.uk/, which has a large selection of his writings online. You can get "Maiden Tribute" at archive.org as well, as a free book for Kindle.