ONCE IN A WHILE, a young girl will show up at the office of a gynaecologist accompanied by her mother.

The mother's complaint: "My daughter has not had her first period yet, but all her classmates already have."

In most cases, the doctor will say: "Nothing is wrong with her. Just be patient, and she will pass this milestone like all young ladies."

However, in some cases, the physician may deliver shattering news.

"She has not menstruated yet, and she never will! She was not created to have periods ... I am sorry, your daughter's not a lady!"

The shocked mother then learns that although her daughter grew up as normally as the dainty girl next door, she carries the XY chromosomes of males and has testicles in her lower abdomen instead of ovaries! Naturally, a mother in such a situation would wish to hear nothing more from the doctor. But neither can any doctor reverse the disorder of an "unrealised male" trapped in a female person! Photographs of "unrealised male" bodies reveal no clue that something is odd about them.

They look like normal girls with well-developed breasts, narrow shoulders and broader hips.

Call them "unrealised males" or "feminised males", they are the most striking example of what could go wrong when messages from hormones that guide development during crucial stages of foetal formation are "blocked" or "mimicked" by imposters.

The opposite may also happen with an "unrealised female" ensconced in a male body.

If anything "meddles" with testosterone or an associated hormone, the foetus will develop a clitoris and other external female genitals.

In less extreme examples of "disruption", males may be born with ambiguous genitals or abnormally small penises and undescended testicles.

For all the body systems to develop normally in a foetus, it must get the right hormonal message in the right dose, to the right place, at the right time.

This biological ballistics is a complex hormonal choreography and it orchestrates itself at a dizzying pace.

Everything depends on timing and proper cues and nothing must come in the way, and cause these messages to get scrambled.

If the cueing is thrown out of whack during the critical formation period, it can manifest in macabre life-long consequences for the offspring human or animal.

The progress of this genetic drama has occupied xenobiotics expert Assoc Prof Dr Mustafa Ali Mohd of the Faculty of Medicine (Pharmacology), University Malaya for over a decade. This is the study of the effects of foreign matter on a system, such as in animal or human bodies, plants or the environment.

Mustafa heads the ShimadzuUMMC Centre for Xenobiotics Studies (SUCXeS).

Based on several research studies conducted at the centre, he says: "Hormones ... going haywire is a major problem for the world out there."

Xenobiotic experts all over the world are recognising the effects of this insidious threat to man and wildlife caused by natural and man-made chemicals.

These chemicals are everywhere in pesticides, paint, industrial products, polymers and plastics, food wrappers, canned products, water bottles and a host of common items used in the home, in cosmetics, sunblockers and in drinking water not to mention, cord blood and breast milk! Hence, nobody is safe from these chemicals, which are disrupting normal sexual development and reproduction and are causing birth defects that are not inherent, as well as suppression of the immune system.

They are major agents of environmental pollution and are also found in the air as in sewerage systems, being part of industrial and domestic effluents.

Inevitably, in the rivers and waterways, they cause sinister hormone agitation in marine life and to the larger mammals that come to drink.

Frogs in certain countries have been spotted with missing limbs and there are reports of a worldwide decline in the amphibian population, whereas fish are afflicted with mysterious tumours.

The birds in the air fare no better.

They, too, have become unsuspecting victims of mutating deformities such as crooked bills, clubbed feet, missing eyes and other congenital disorders and a bizarre wasting syndrome that would apparently strike healthy birds that suddenly wither and fall from the sky.

The recent case of four flying pigeons that fell from the sky at a private college in Petaling Jaya was not a case of avian flu.

So what caused their hideous crash-and-die suicidal syndrome?

Strange as it might seem, perhaps, we may soon be hearing of bald-headed eagles losing their baldness! The term endocrine-disrupting chemicals (EDCs) is not the kind of phrase that is likely to be found in normal conversations.

But for scientists like Mustafa, it accurately describes the impact of these chemicals on animal and human hormones.

Apart from being a genderbending agent, EDCs are also known to cause low sperm counts, and a high incidence of testicular and prostrate cancers as well as reduced proportion of male births worldwide.

They are also responsible for the current worrying trends in women's health.

Research results point to EDCs for the dramatic rise in hormone-related cancers (breast and ovary), endometriosis and other disorders affecting increasing numbers of women today.

Plunging headlong into promising new chemistry-based technologies at the turn of the century, industry has unwittingly unleashed unknown health threats in our midst.

Today, we may have inherited a dark chemical legacy that can no longer be wished away or, perhaps, even undone.

A costly war has to be waged out there against EDCs by governments, industrialists and the international community.

As you read this story, mothers are continuing to pass this "dark inheritance" through their wombs and breast milk to future generations.

Here we are, with an impending apocalypse in our hands that must be stopped as it wreaks havoc to our hormones.

And the time is now or there will be no winners in this war.

Perhaps, only "survivors" and it will be dreadful to imagine what our future generations will look like!