We have heard a lot about a new era of personalised medicine - some of it pretty wild speculation about miracle cures - that would follow in the wake of the Human Genome Project.
According to President Bill Clinton it would "revolutionise the diagnosis, prevention and treatment of most, if not all, human diseases."
We were "learning the language with which God created life" and with this profound new knowledge "humankind would gain immense new power to heal".
Maybe this was hyperbole, but a study published today in the journal Clinical Science does help paint a picture of what this Brave New World of personalised medicine may actually look like.
The research, carried out by Prof Somnath Mukhopadhyay, at the Brighton and Sussex Medical School and colleagues at the University of Dundee, focuses on the substantial minority of severely asthmatic children who respond poorly to the leading conventional drug treatment, Salmeterol.
The drug, is found in Seretide and Servant inhalers, acts on beta-2 receptors in the lining of the airways, but previous research has shown that as many as one-in-seven children carry a gene variant - arginine-16 - that undermines its effectiveness.
"For these children," Prof Mukhopadhyay said, "the leading drug treatment simply doesn't work, and there's some evidence that their condition may even be aggravated by the use of a long term controller medicine that isn't helping".
The study showed that by substituting salmeterol for an alternative anti-inflammatory medicine, montelukast, outcomes for severely asthmatic children with the arginine-16 gene variant were substantially improved.
The children experienced increased quality of life, and attendance at school and in sports activities improved, while the number of visits to out-of-hours GPs' surgeries declined.
You can read more about the study here, but perhaps its real power comes as a demonstration of the shape of things to come.
For the price of a simple spit test - about £15 a head - existing treatments for a chronic and debilitating condition can be revised and tailored to fit a specific genetic sub-group within a population.
"For the first time, we've shown that personalised medicine can work in the field of childhood asthma," professor Mukhopadhyay says. "It's a pretty striking result."
Professor Stephen Holgate, the MRC clinical professor of Immunopharmacology at the University of Southampton, agrees.
"This is a wonderful example of stratified or personalised medicine working its way into practice. While still a small trial the results are impressive," he says.
It may not measure up to the "language with which God created life", but the better targeting of existing medicines within groups of patients may show us how the hype over personalised medicine could begin to be realised.