The content of the messages, Gemma says, included graphic sexual terms her and her husband had to look up online, as well as offers for unprotected sex and details of where to get it.
Now she's calling on police and policy makers to be more vigilant in monitoring the sex industry. She wants them to know how easily the industry is accessed by minors. It's as easy as firing off a text, she says.
"Hey, how are you? Just wondering if you're still offering cream pie service? I'm clean, 24 and I'm (sic) good shape," her son had written in response to an advertisement.
"Hi, yes I am still offering a creampie service, I'm just not available tonight for incalls as my hotel options are closed for checking in," the response read.
"I am free every day and night thought (sic)."
In other messages, the teen asked if it was possible to have unprotected sex. On every occasion, the response was a firm "yes".
"Can I come there?" the teen asked. "Prob start first sesh for 2 hours and see if we hit it off. I'll bring some party so we can chill a little too."
A woman advertising her services on backpage responded immediately: "Okay sweet well can we lock in a particular night? Like could you make it down here tomorrow night and I'll grab a nice apartment near the bay? Just FYI 2 hours is $900 full (natural) service."
On no occasion was the teen asked to verify whether he was over the age of 18. Gemma told news.com.au she couldn't believe how quick the responses came through and how casual they were.
She said her son and his friend found the listings while browsing on their phones at school and that he is "embarrassed" that his conversations have been outed.
"He was grounded and so we took his phone off him," Gemma said. "A reply came through and we were naturally concerned, so we got his password, opened his phone and that's when we discovered all these messages from so-called escorts from backpage.
"Language in the texts advertised unprotected sex, no questions asked. They said 'yes', gave a price and an address. Imagine if my son had've met up with these escorts. What could've happened? What could've been waiting for him? It's not just a massive concern about sexual safety — it's physical safety."
In Victoria, it is not illegal to operate a brothel, but the Sex Work Act makes it illegal to cause or induce a child to take part in a sex act.
Grooming offences in Victoria state that a person over 18 can't communicate with a person under 16 with the intention of facilitating a sexual act between the parties. There are different laws in each Australian state and territory.
Gemma says "nobody is policing" online classifieds, despite how openly they advertise sex.
"We can't understand why nobody is doing anything about it," she told news.com.au. "Nobody really cares. I don't think anyone will care until it happens to their own child."
After discovering the messages, Gemma and her husband did some investigating of their own. They went to backpage.com and collected information, including ad numbers, phone numbers and services offered without question. A spreadsheet documenting what they found includes 28 separate mobile numbers, almost all of which belong to escorts offering unprotected — or "natural" sex.
The mum-of-one says she's not out to attack the industry but wants it to be better regulated.
"We don't have an issue with legal prostitution, we understand it's a job for some people. It's just so wrong that this is so accessible."
Gemma phoned a number of legal brothels operating in Victoria. She was told offering unprotected sex was illegal but offering sexual services online was not.
Backpage.com was seized by the FBI last month and its co-founder Michael Lacey was charged with helping mastermind a scheme to use a website to sell sex. According to The Australian, Mr Lacey pleaded not guilty to state and federal charges and was ordered by a magistrate to wear an electronic bracelet to monitor his whereabouts.
Backpage.com's chief executive, Carl Ferrer, pleaded guilty to conspiracy and money-laundering charges. The website reportedly generated more than $US500 million ($AU643 million since launching in 2004 and was second only to Craigslist in terms of users.
News.com.au has contacted Victoria Police for comment.
*Gemma's name has been changed to protect her and her son's identity.
