However, the majority of parents defended Alice's decision.
"This is what my older sister did. Her son potty trained himself by 2.5yr because there was no pressure to do," another said.
"I can agree with this; we put a small toilet for him in the bathroom for whenever he was ready and one day he just magically started going himself at three years," one person wrote.
"This is what I did and my son was fully using the toilet, day and night, at 18 months. It took three days," another claimed.
Alice's stance on toilet training is actually similar to a well-used method known as "child-oriented toilet training".
Using this method involves parents talking about using the toilet and offering it as an option to children aged between 2 and 3, Healthline reports.
Rather than pushing children to begin using the toilet within a set time, it encourages them to move away from nappies at their own pace and because they want to fit in with the people around them.
The US mum says she's allowing her son to toilet train himself when he's ready. Photo / @growingupfern
It was developed by paediatrician T. Berry Brazelton in 1962, with research suggesting it can be one of the most successful types of toilet training.
Back in May Alice revealed that she didn't stop Fern from putting whatever he wanted in his mouth.
This included sticks, rocks, dirt and sand as well as licking "unsanitised shopping carts".
"I do not fear bacteria. In fact, I welcome it. I trust nature and my baby. It is not a coincidence babies have this instinct while they are breastfeeding," she said in a video.
While letting babies consume a small amount of bacteria from objects put in their mouths can help "boost immune systems", sand and dirt is known to host dangerously high levels of bacteria and can cause breathing problems when inhaled.
Alice's video sparked massive debate among people, some of whom argued they ate dirt as a kid and grew up "fine".
