Parents of twins have often said that their children appear to communicate using a secret language. Now, recent studies appear to be unlocking the hidden messages contained in their very genes.

Researchers are increasingly using twins to study how genes affect everything from autism susceptibility to whether or not someone will be a productive employee. Identical twins carry the same DNA while fraternal twins share 50 per cent of their DNA, making both sets unique subjects for looking at the role genes play versus environmental factors.

The results of a recent study of identical twins in Sweden suggest that your genetic makeup determines whether you will be a spender or saver.

The study found that the spending habits of identical twins were more than twice as likely to be the same as the spending habits of fraternal twins.

Identical twins share the exact same genetic makeup, while fraternal twins share 50 per cent of their genes.

While parents and teachers may be able to influence a young person’s spending habits, the researchers said, it appears the impact of those lessons will diminish as he or she gets older.

Meanwhile, researchers in nearby Finland have used twins to investigate just how much of an impact exercise has on the body and the brain.

Twins whose personal health regimens had been very similar as they grew up but had diverged in adulthood produced very different results during fitness and metabolic health tests.

The sedentary twins had lower aerobic endurance, higher body fat percentages and early signs of insulin resistance. The more active twins had more grey matter in their brains, particularly in the regions implicated in motor control and co-ordination.

Because the twins’ lives were so similar before their exercise regimens became different, the changes in their health likely occurred after that time, the researchers said.

This means that establishing and sticking with a consistent exercise regimen can significantly impact our health and fitness levels, no matter what our genes say.

And twins recently helped researchers in the United States identify a gene mutation that may allow the carrier to function normally on less than six hours of sleep per night.

The study included 100 pairs of twins. Researchers at The Children’s Hospital of Philadelphia found that twins who carried the mutation p.Tyr362His, a variant of the BHLHE41 gene, slept on average for about five hours a night. The non-carrier twins slept for just over six hours.

However, the twin with the gene mutation who slept less had on average 40 per cent fewer lapses of performance during 38 hours without sleep and required less recovery afterward. These twins only needed eight hours of sleep after the extended period without sleep, compared to the twin, who slept for 9.5 hours.

The researchers concluded that while our need for sleep is a “biological requirement and not a personal preference,” there are those people who can sleep for less than six hours per night and not experience any “daytime dysfunction."