Other questions that spring to mind

SEX AND ALL THAT...
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The Independent Culture
The hypothesis of foetal programming begs some fascinating questions. If it's true that the foetal adaptions to nutrients and oxygen programme our susceptibility to cardiovascular disease then, its proponents ask, what else might it programme?

Other research teams have already linked low growth rates in utero with damaged airway growth and chronic bronchitis. But could foetal favour- itism perhaps also hold some the answers to the devastating degenerative conditions of biological ageing such as Alzheim-er's disease, osteoporosis and blindness?

The Southampton team says maybe. It's possible, they say, that every foetus has to make a certain number of choices about how much of its resources to allocate to growth and hence reproduction, or to the body's repair mechanisms.

An undernourished foetus would tend to go for growth because its agenda is to get the DNA into the next generation and never mind repair as long as the body lives long enough to fulfil its evolutionary duties.

There is already evidence to support this choice. Some studies have now discovered that girls who are smaller at birth tend to begin their periods at an earlier age, indicating that perhaps even in utero the foetus may be registering the possibility of a shorter reproductive life span and therefore resetting puberty to ensure that the woman it becomes can get going early.

And what about sex? If the foetus can reschedule puberty with its series changes in response to undernutrition, might adaptations made in the womb be the key to altered sexual orientation?

A simple hormonal spurt during a critical period five to 10 days after birth is what sets our psychological gender. In experiments with rats as long ago as 50 years, scientists discovered that tinkering with the levels of sex hormones circulating on day five after birth, permanently changed both the rodents' sexual drive and behaviour.

Females injected with testosterone developed a female physique by puberty but never mated or showed any wish to. The hypothalamus, which governs the circulation of sex hormones that distinguishes female from male, had been imprinted with a sexual memory at odds with the physical growth. A similar injection five days later changed nothing.

The question that we really have to ask is, what is it that controls the once-only burst of hormone? And if foetal malnourishment at critical periods in development can change our glucose metabolism, alter the output of enzymes in our liver and interfere with the structure of our veins for the rest of our lives, then what havoc could it wreak on such a perfectly timed schedule?

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