Apparently, they use the humans to fight their offspring to weed out those with genetic weaknesses, as only the strongest would survive.

So that it can infect others of that species better, and faster, by adding the newly infected's genetic weaknesses to the virus's very genome.

Of course some do not show their genetic weakness - or strength as we call it - until they are adults.

Incontinence can also be caused by multiple pregnancies, being overweight, and genetic weaknesses.

Icelanders may not possess the full spectrum of human genetic weaknesses, or they may have them with different frequency.

She had shown a genetic weakness in the testing for license and hadn't been allowed to breed.

No people with any genetic weaknesses were allowed to produce a child, so the outcomes were pretty predictable.

"So, your family has this weird genetic weakness for disappearing into the wilderness and running with a pack of wolves?"

They have also argued that mulesing may mask genetic susceptibility to flystrike allowing for genetic weaknesses to be continued.

This was made possible by a genetic weakness introduced into the humans, but not the Monoids, by a second wave of the cold virus 700 years earlier.