Heather Simpson seemed to be doing all the right things to potty train her two-and-a-half-year-old son, Jimmy. She and her husband waited until six months after Jimmy’s little brother was born. The potty was left out for easy access. They used a sticker reward chart to celebrate Jimmy’s efforts. He soon mastered peeing in the toilet…but number two? That’s another story. Jimmy was clearly disinterested in using the potty for that, thank you very much. “At one point I offered him an entire box of Smarties for a poop in the toilet,” says the Toronto mom, who asked that her name be changed.

Sound familiar? Whether they’re withholding for days or refusing to do it sans diaper, parents who’ve potty trained know that teaching tots where to poo doesn’t always go as planned. “This is a common reason why doctors see children,” says Dr. Mia Lang, an assistant professor of pediatrics at the Edmonton-based University of Alberta.

The range of poop-related problems is wide – so here’s a quiz to help you get to the, er, bottom of things.

When your child is ready to poop, he
A. cries
B. demands a diaper
C. wants to stay standing

What sound does your kid make when she’s going?
A. a drawn-out, loud grunt
B. nothing – we can’t hear her when she’s hiding behind the couch
C. a little pushing sound

Which applies to your child most?
A. he holds it for days
B. he’s scared of touching the toilet
C. he thinks he’ll fall in the toilet

Mostly As:
The problem could be pain-related. “Children often strain to push the stool out, which can tear the tissue near the rectum. This is called an anal fissure,” says Dr. Lang. That means your little one might associate pain with doing the movements, and as a result, may withhold for days, even weeks – Dr. Lang has seen children withhold for as long as two weeks, at which point they may need an enema. “Withholding makes the stool harder, larger and more painful to pass. Then the intestinal wall can stretch out, and they can then lose the sensation of a full rectum and temporarily lose control of it,” she says. So what to do? Try bulking their diet with fibre-rich foods to help make stools easier to pass. Water, whole grain foods and fibrous fruits and vegetables such as berries, apples and peas will do the trick. (Avoid bananas, which add to constipation, for a few days.)

Mostly Bs:
The problem could be behavioural. If your mini-Houdini vanishes when he needs to poop, or only poops in Pull-Ups, he could be simply avoiding the fuss that comes with the whole process, says Dr. D. Preston Smith, a pediatric urologist and author of The Potty Trainer: The Ultimate Guide to Potty Training Your Child (PottyMD). “They hide their actions so they can just do the poop and get back to playing fast,” he says. Streamline your wiping and washing routine – and tone down all the hygiene talk – and the process will seem like much less of an imposition. Or, you could have a frightened flusher on your hands – plenty of kids are a little concerned that they might just disappear down the toilet, too. If this is the case, desensitize your child to the flushing process. Invite her to dry her hands with toilet paper after washing and flush it, or even (if you’re comfortable with this!) flush after you’ve finished.

Mostly Cs:
The problem could be position. Sure, lots of kids go standing up – so isn’t the switch to sitting harder for them? “You’re likely to empty better if you’re sitting,” says Dr. Smith. “To be effective, you should be flexed at the hip.” Once your kid puts this together, he may be over the hump. For proper positioning, his feet should rest comfortably on the floor, or on a stool, and his legs should be gently spread apart.

In the, um, end, Dr. Smith also says it’s about making a clean break from the diapers. “It’s just like the pacifier,” he says. “You might have some accidents and frustrations, but if you take a day or two out of your life when you’re not running errands but spending a lot of time loving your child while saying you’re going to do this, you will get him to poop in the potty. And he will still love you.”