"She said no one had said she couldn't bring him, it's good life experience etc. I said no and she agreed (eventually) for him to wait in reception."
The situation worsened, however, when the woman was told she hadn't scored the job.
"When I called her to say she hadn't got the job, she said we were discriminating against her because she had a child," Caulk wrote.
"I don't think I was unreasonable, but no one ever does. What would you have done?"
Unsurprisingly, the forum was flooded with people who confirmed the mother was wrong in trying and bring her child along to a professional interview.
One Mumsnet user posted: "She wonders why she didn't get the job after essentially arguing with an employer BEFORE the interview even started?! She sounds unhinged."
Meanwhile another said, "What a weird thing to do ... I'm cringing on her behalf," and another said the mother's behaviour was "very unprofessional and inappropriate".
But others pointed out that the mother's odd decision had probably been a blessing in disguise.
"Sounds like she did you a favour by demonstrating how bats**t crazy she was straight away," someone posted, while another user wrote: "You could have ended up giving her the job and spent the next two years trying to get rid of her and then fighting the subsequent unfair or constructive dismissal claim that she would have inevitably brought against you."
Others were inspired to share their own bizarre job interview anecdotes, with one woman revealing she had once interviewed an adult woman who "brought her dad with her".
Another shared a story which happened to a friend of hers.
"My best friend was interviewing applicants for a teacher's role," she explained.
"This guy turned up — T-shirt and jeans and trainers, 15 minutes late, carrying a coffee and pastry. 'Hi guys, sorry I'm a bit late, I didn't have time to have my breakfast so stopped at Costa.' He didn't get the job."
And some found the situation so strange they questioned whether it was all a "wind up" organised as a prank by the woman's colleagues.