precision medicine

Federal researchers are collecting blood samples from 1 million Americans as part of an effort called "precision medicine." But some critics worry that the path ahead is expensive and unclear.

The goal is to customize treatments for cancer and other diseases to a patient's own biology. But something as simple as failing to take care of tissue samples en route to the lab can derail that.

Hundreds of millions of dollars are pouring into research labs in an effort to collect genetic information on a million people. But some skeptics say the focus should be on humans themselves, not DNA.

Holding out the promise of major medical breakthroughs, President Barack Obama on Friday called on Congress to approve spending in medical research that…