Some unfortunate souls are born to be mosquito magnets, new research suggests.
Scientists have found evidence that people's genes determine how attractive their body smell is to the biting insects.
The findings build on previous work linking body odour to the chances of being attacked by mosquitoes.
Some individuals who avoid being bitten were shown to produce a natural insect repellent that kept them safe.
The new study found that identical twin pairs were more similar in their attractiveness to mosquitoes than non-identical twins.
Since identical twins share all the same genes and non-identical twins do not, this was evidence that the mosquito effect was genetically driven.
The trait had about the same level of heritability as height and IQ, the research showed.
Lead scientist Dr James Logan, from the London School of Hygiene & Tropical Medicine, said: "By investigating the genetic mechanism behind attractiveness to biting insects such as mosquitoes we can move closer to using this knowledge for better ways of keeping us safe from bites and the diseases insects can spread through bites.
"If we understand the genetic basis for variation between individuals it could be possible to develop bespoke ways to control mosquitoes better, and develop new ways to repel them. In the future we may even be able to take a pill which will enhance the production of natural repellents by the body and ultimately replace skin lotions."
The study involved 18 identical and 19 non-identical twin pairs. In the experiment, Aedies aegypti mosquitoes - which transmit dengue fever - were released into a Y-shaped tube that allowed them to choose between the hands of different study participants.
Female mosquitoes are known to display an odd preference for certain people when looking for a blood meal.
Pregnant women are more attractive to the malaria mosquito Anopheles gambiae than those who are not pregnant. And fatter people also seem to be more attractive to mosquitoes and midges than slim individuals.
Diet has previously been suggested as a possible explanation, supporting old wives' tales about eating garlic or drinking beer to keep mosquitoes away.
But the diet theory is not backed by any clear scientific evidence.
The new findings are published in the online journal Public Library of Science ONE.