New cries over how the milk spills. (problems related to use of growth hormone in cows)

Dairy farmers have begun injecting cows with a growth hormone in order to produce more milk, and it's making people nervous. Hormones, after all, are often automatically associated with steroids. And growth hormones sound like substances that can dangerously accelerate the physical maturation of young girls and boys, who drink lots of milk for their body size.

More disconcerting still, the hormone in question is produced via genertic engineering, a type of technology by which genes are altered in a laboraory thereby conjuring up images of mad scientists involved in a dangerous cloning process. But although a number of health as well as environmental professionals have concerns about the hormone's recent approval for sale by the Food and Drug Administration, most are not concerned that milk will become tainted.

One reason is that cows produce the hormone naturally. That is, it has always been present in the milk we drink. Secreted by cows during lactation in order to stimulate milk production, it's called bovine somatotropin (BST) and is sometimes referred to as bovine growth hormone (BGH).

All that happens when BST is produced in the lab and the injected into cows is that it increases milk production anywhere from 10 to 25 percent. The milk that ensues is identical in taste, appearance, and nutritional value to milk made without it--so close in resemblance that scientists…