A doctor has revealed the one body part which can determine the size of someone’s penis – and it’s not the one you’re thinking of.

There’s no shortage of methods people claim will give you an indication of the true size of someone’s manhood, however most of these are urban legends.

Which is certainly good news for any men with small feet who may have spent years being the butt of the ‘big feet = big d*ck’ comments.

According to a recent TikTok video from Dr Karan Rajan there is one way you can garner the size of a man’s downstairs region – and it has nothing to do with the feet.

If you’re desperately curious then it’s time to whip out the tape measure and grab the hand of your target, as it turns out men’s digits can tell us a lot about other parts of their body.

In the video Dr Rajan claims there are two particular fingers to pay attention to, the ring finger and the index finger.

Substituting the word penis for the more TikTok friendly term of cactus, he said: “You can guess the size of a man’s cactus by how short his index finger is.”

Explaining that the science behind the argument comes from the Asian Journal of Andrology, Dr Rajan said it’s all down to the size of your fourth finger in comparison to the second.

“A shorter index finger compared to ring finger correlates to a bigger schnozwangler,” he continued.

Branding it the ‘second to fourth digit ratio’ the doctor explained that all you need to do is divide the length of the index finger by the length of the ring finger and voilà, you have all the information you need.

In case your wondering how finger length correlates to the length of other appendages on the body, a shorter index finger equals a lower ratio – which means a bigger dong.

This is caused by high ‘exposure to testosterone in the uterus’, with the study claiming that in utero exposure to testosterone is responsible for the size of the fingers and penis (sorry toes).

While there is plenty of research behind second to fourth digit ratio and its connection to testosterone exposure it is unlikely to be an universal rule, with many viewers claiming to be the exception to this argument in the comments section of Dr Rajan’s clip.

Perhaps it’s worth taking the research with a pinch of salt then. After all, we’re all aware of the age old saying ‘it’s not the size that matters…’