You can read the research published in the Journal of Paediatrics and Child Health here.
The six paediatric healthcare professionals from the website Don't Forget The Bubbles, based in the United Kingdom and Australia, each swallowed the head of a Lego character and measured how long it took for the body to excrete it. In this case, it was a lego head that they swallowed.
The participants in the study, three men and three women, were all paediatric professionals themselves and therefore presumably more dedicated to the cause than the man on the street. They got six adventurous volunteers to dine on Lego heads, and then poke around after each potty run until they spotted the bright plastic pieces in their poop.
The doctor's Stool Hardness and Transit score (SHAT) was measured beforehand as a control for the experiment.
The average FART score *giggles* was set at just over 1.7 days, indicating the amount of time between the specialist eating the Lego and it being found in their stool. The amount of time it took to travel from mouth to toilet was also aptly titled - the Found and Retrieved Time (aka the FART) score. "This will reassure parents, and the authors advocate that no parent should be expected to search through their child's feces to prove object retrieval", the authors wrote in the study.
The SHAT results showed that the consistency of the researchers' stools were not affected by the object they swallowed.
There was some evidence females may be more accomplished at searching through their stools than males but this could not be statistically validated.
Unfortunately for one of the participants, the little Lego head was never discovered in his stool.
Though she hopes the study will make people smile, Leo told the Guardian that parents still need to seek medical attention if their children swallow anything "sharp, longer than 5cm, wider than 2.5cm, magnets, coins, button batteries or are experiencing pain".