A Canadian doctor has taken to TikTok to educate users on the rare instances where sets of twins are born to different fathers.

Dr Michael Narvey, a newborn intensive care specialist from Winnipeg, Canada, addressed followers on his channel, providing a simple explanation as to how this ‘exceedingly rare event’ can happen.

An unusual occurrence

The video, which has been viewed over 15,000 times, saw Dr Michael going into detail about the rare phenomenon of superfecundation in humans.

Superfecundation, which is common in animals such as cats, dogs, and cows, can happen in two ways.  

The first is when a woman has sex with two different men prior to ovulation. Sperm is then present in the fallopian tubes when two eggs are released.

It can also happen when a woman has sex with two different men after she has ovulated, and the sperm are then able to fertilise two eggs.

Viewers of Dr Narvey’s channel were baffled by the revelation of superfecundation in humans, despite it being common among other species as a way of ensuring multiple offspring.

In humans the chances of superfecundation occurring are slim. There have been fewer than 10 cases recorded worldwide, although there are likely to be more that are not known about.

Reliable twin testing from AlphaBiolabs

A UKAS-accredited laboratory, AlphaBiolabs provides a range of DNA testing services for members of the public, including twin DNA testing.

For just €139 for next day results, or an additional €50 for same day results, our Twin DNA Test is the fastest in Ireland.  

Using a simple cheek swab, twin testing – also known as zygosity testing – can be used to determine whether multiple children from the same birth are identical (monozygotic) or not (dizygotic).

Call our Customer Services team on 01 402 9466 to find out more or email