I appreciate Pierre's Schembri Wismayer's lengthy and detailed reply (Of Life - And Women - Of All Ages, October 30) to my letter, however, I still feel that he has evaded the main argument I put forward (Life Without Fertilisation, October 26) and still hasn't explained why he feels that fertilisation is of special importance in forming a unique human life. Dr Schembri Wismayer's opinion on this matter is particularly vital since he is the appointed stem-cell expert on the advisory board of Malta's Council on Science and Technology.

If he feels that the fertilised human gamete should be protected because of its human potential, then should not the human sperm and human ovum not also receive the same privileged treatment?

Do ovum gametes not have the same human potential as a fertilised zygote, despite somewhat less favourable odds of reaching their full potential?

Secondly, human zygotes arising naturally without fertilisation (such as is seen in ovarian teratomas, which are foetal growths found incidentally in young women, and which rarely may even be present in men) may contain unique DNA profiles, and may also have fully formed organs such as teeth, skin, a beating heart and sometimes even functional rudimentary brain tissue. Should this foetal tissue, which has reproduced without fertilisation, not therefore be given the same protection as an anencephalic foetus of fertilised origin? After all, according to Dr Schembri Wismayer's reasoning, neither of these foetal forms, whether resulting from sexual or asexual reproduction, would ever reach their full human potential. On what basis is he discriminating between these two human foetal forms?

I remain puzzled as to what scientific basis he has used to select the single and very specific step of fertilisation as being the earliest determinative step in the formation of a human individual, when scientific evidence has proven that fertilisation is neither crucial nor particularly determinative in initiating unique human life, a lengthy process that, as he admits, may begin many years before fertilisation even occurs.