World Population 
Parkes: That is perfectly true. Ovulation is a minor source 
of loss of eggs. In most experimental animals if an ovary never 
ovulated it would alter very little the time of exhaustion of the 
odcyte population, and persistence of functional odcytes would 
not, I think, postpone the time when the pituitary stopped 
functioning. 
Hoagland: Some women who have been taking the con- 
traceptive pill Enovid have gone through the menopause at the 
normal time, haven’t they? 
Pincus: ‘The number is still very limited, but there is no 
question that several of them gave indications of entering the 
menopause. On the other hand there are some who continue 
to be cyclical a little longer than we expected them to. So we 
cannot make a definite statement. 
Koprowski: On the basis of figures of the incidence of 
malignancies in women taking Enovid and those acting as 
controls, would you advise women in a country consisting of, 
let us say, 100 million people to take en masse either Enovid or 
any of the other drugs used in this study? 
Pincus: No. That is why we are increasing our observations 
by a large factor. Professor Klein put his finger on what is the 
key question in this area: the differences between studies on 
experimental animals and human beings. In experimental 
animals this problem has been tackled very intensively; large 
dosages have been given to laboratory animals, including 
monkeys, over periods of several years, and the incidence of 
malignancy among these animals is certainly no greater than in 
untreated animals. However, one can also raise the question 
of the human being as a cancer-susceptible individual. It is my 
impression that the genes involved in permitting the develop- 
ment of cancer in the human are on the whole not present in a 
great majority of people, and I don’t think that the compounds 
we are using would uncover the genes. But this is still a possi- 
bility in old age. The figures which we have obtained on 
malignancy were acquired in routine examinations. They 
indicate that there is very little chance of an immediate 
precipitation of malignancy in large amount. I might add that 
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