We can learn a lot of important lessons about genetics from Disney. For example, from The Muppet Christmas Carol (released in 1992 by Walt Disney Pictures) we learn that the being a frog genes are on Kermit’s Y chromosome. Thus when Kermit and Piggy have children, the boys are all frogs and the girls are all pigs. We also learn that Muppet frogs and pigs are close enough as species to interbreed, although we can’t comment how close without observing the fertility of their offspring. These are slightly more confusing lessons. I also assume that the reason that Muppet Tiny Tim couldn’t walk well, was that he was actually still a tadpole and just had pushy parents. After all there’s only one more sleep until metamorphosis.

The biological processes behind Beauty and the Beast are slightly more difficult to work out. Mrs Potts is a teapot and her son, Chip, is a cup. We know that the curse that transformed the servants of the castle into theatrical IKEA stock had been in place for 10 years. Chip seems younger than this. It should be hoped that from the moment they were transformed, the staff didn’t age and that young Chip was one of those who the witch literally made a mug of when she cast her spell. Otherwise we have to consider the idea that a teapot got pregnant and gave birth to a cup. A tale as old as time.

The biological variation within that happy crockery family is far from unique within the world of Beauty and the Beast. A person conducting a preliminary comparison of Belle and her father, Maurice, would be hard-pressed to find much of a family resemblance. Belle is tall and slim, while Maurice more closely resembles an owl that rolled itself in pastry and finished the disguise with a moustache it fashioned from leftover rodent hair. I’m not judging. I have a similar body type. The same could be said of Aladdin’s the Sultan and his daughter, Princess Jasmine. Again Jasmine is tall, with barely enough abdomen to contain her colourful Disney internal organs, while the Sultan is practically spherical and would struggle to see over a crouching slug while he was wearing platform shoes. For this to work, Jasmine and Belle’s mothers must have been 10 feet tall and essentially boneless. Either that, or Disney fathers are constructed entirely from recessive genes.

We don’t have to guess at the heights of Jasmine and Belle’s mothers. These can be calculated from the heights of the princesses and their fathers. Within medicine, a person’s adult height can be estimated from their parents’ heights, using an estimation called the mid-parental height. The calculation is as follows:

Mid-parental height = Mother’s height plus Father’s height (plus 13 for boys, -13 for girls) and divide by two.

NB: Heights are in centimetres (cm).

This method isn’t perfect. For example, it doesn’t allow for extremes of parental height. Very short or very tall parents tend to have offspring of a less extreme height through simple regression to the mean. This wouldn’t be predicted by the mid-parental height estimation. However, it is a useful tool to help assess an individual child’s growth and to calculate the height of fictional princesses’ mothers. By rearranging the equation, we find that

Disney Mother Height = (Disney Daughter Height x2) plus 13, minus Disney Father Height

This idea can be tested in cases where we see both of the parents and the daughter e.g. Aurora in Sleeping Beauty and Rapunzel in Tangled.

Unfortunately, Disney doesn’t provide us with the vital statistics of the characters. Which is pretty thoughtless of them. As a result, we’re going to have to make some crude estimates. In Sleeping Beauty, Aurora’s father can be seen holding a wine bottle. Given that he ended up sleeping for 100 years, it must have been some pretty strong stuff. Or a witch did it. A standard wine bottle is approximately 30.5 cm and from a couple of stills from the film, Aurora’s father looks to be about 5.8 wine bottles tall. As a side note, if you start to measure you’re height in wine bottles, it might be time to take out the recycling. This may not be the least of your problems. We can therefore estimate Aurora’s father to be 176.9 cm (5 ft 10 inches) tall. From more stills, Aurora’s mother looks to be the equivalent of Aurora’s father’s head shorter than Aurora’s father. A human is roughly 7.5 heads tall so Aurora’s father’s head must be 23.6 cm, which makes Aurora’s Mum 153.3 cm (5 ft 1 inches) tall.

From the film, Aurora comes up to her father’s shoulders and so appears to be about 153 cm (5ft) tall; similar to her mother. Using the mid-parental height equation, Aurora’s height is estimated at 158.6 cm (5ft 2 inches). So we’re about 5 cm off. However, in Sleeping Beauty, Aurora is 16 years old. A woman’s final adult height can be reached at around 18 years of age, so perhaps it’s not impossible for her to grow those last 5 cm, especially if she manages to eat well and get plenty of sleep. This probably isn’t a problem.

We can test our height prediction in a similar fashion with Rapunzel from the film Tangled. In one scene, Rapunzel’s mother is observed holding a book. If we assume the book to be one octavo (a unit of measurement which should be familiar to Terry Pratchett fans, and is approximately 15.3 cm) and we can see that Rapunzel’s mother is about 10.5 books tall. We can guess Rapunzel’s mother is 160.7 cm (5ft 3 inches) tall and that her librarian is messy. Rapunzel’s father is roughly another book taller than Rapunzel’s mother, making his height 176.0 cm (5ft 10 inches).

From pictures, Rapunzel is about one third of her mother’s head shorter than her mother. If we estimate her mother’s head to be 21.4 cm long, this gives Rapunzel’s height as 153.6 cm (5ft). The mid-parental height calculation predicts Rapunzel’s height as 161.9 cm, so we’re about 7 cm off. As with Aurora, Rapunzel may still grow a bit more (although she’s 18 years old in the film) and we might argue that she is shorter due to being mistreated and held captive in a tower. Perhaps the weight of all that hair is compressing her spinal column and making her shorter. Overall, our height estimates using mid-parental height are within 10% of what we see on screen, so should be adequate for estimating the heights of Jasmine and Belle’s mothers.

In Aladdin, at some stage, both Jasmine and the Sultan are shown next to their pet tiger. A male tiger can be 110 cm from the ground to the shoulder. Judging by where the tiger comes up to on Jasmine, we can estimate her to be 170 cm (5 ft 7 inches) tall. Similarly, we can estimate the Sultan to be 130 cm (4 ft 3 inches) tall. The tiger method for measuring height is an exciting one, but probably won’t catch on with parents. It’s difficult to see the pen where you’ve marked-off your child’s height on the side of a tiger. Also, it’s a tiger. Using the Disney Mother Height Calculator, Princess Jasmine’s Mum’s height is estimated to be 223 cm (7ft 4 inches).

To put this height into context, the World’s tallest living woman, Siddiqa Parveen is estimated to be 7ft 8 inches tall (2.1 tigers, 15.3 books or 7.7 bottles of wine). Although of course she isn’t animated. Or fictional. And we cannot work out Siddiqa Parveen’s mother’s height using the Disney Mother Height calculator. That would be a ridiculous waste of time. There are other reasons.

Now it’s Belle’s turn. Luckily, in Beauty and the Beast, both Belle and her father get attacked by wolves. Luckily for us anyway. Like most wolf attacks, it’s shown as a bad thing in the story. An adult wolf is approximately 83 cm from ground to shoulder. In terms of height, Belle looks to be a double wolfer, coming in at 166 cm (5 ft 5 inches) tall. Belle’s father, Maurice, is approximately 1.67 wolves tall and therefore has a height of about 138.6 cm (4 ft 7 inches). Using the Disney Mother Height Calculator, Belle’s Mum’s height is estimated to be 206.4 cm (6ft 9 inches).

Of course, all of this assumes that Maurice was Belle’s biological father and that the Sultan was Jasmine’s. It’s likely that they were. Belle had a whole library at her disposal, so you’d think she’d have the necessary information to hand to work out if her father wasn’t related to her. Although she may have been to busy buying new furniture. All of hers recently turned into people after all.