I thought the sex was already determined at conception, but recently I read this in the newspaper:
“More chance of giving birth to a daughter if you skip breakfast
Women who eat little or who skip breakfast before conception are more likely to have a girl. Conversely, women with a high energy intake increase the chance of having a boy. British scientists write this on Wednesday in the journal Proceedings of the Royal Society: B Biological Sciences.
They examined 740 women in Britain who were pregnant for the first time. They found that 56 percent of the women with “the highest energy intake” had boys, compared to 45 percent of the group of women who ate less. The average energy intake in the women with boys was 2,413 per day, compared to 2,283 calories in the women with girls. The women with boys also had on average a more varied diet with more vitamins C, E and B12, and more calcium.
If a woman skips breakfast, blood sugar drops and the body can interpret this as food scarcity, and thus as an evolutionarily imprinted genetic signal to give birth to girls. The same phenomenon is observed in many animals. According to the authors, this study may explain why many women in developed countries are having fewer boys. The birth rate of boys in industrialized countries has been declining at about 1 percent per year for the past 40 years.”
Answer
You are right, the sex of a baby is already determined at conception, and you can no longer influence that after conception, because gender is an important characteristic that is genetically determined.
As you may know, each of us has 23 pairs of chromosomes. 22 of those chromosomes come in pairs (they contain the same genes, 1 chromosome comes from our mother, and 1 comes from our father), but the 23rd determines our sex. Women have two X chromosomes, while men have 1 X and 1 Y chromosome.
Eggs and sperm contain only 1 chromosome of each pair (we call them haploid, where all other cells in our body are diploid), because they are made of other cells (with 23 pairs of chromosomes) that are split in two, with each new ( egg or sperm cell gets exactly one of each pair of chromosomes. So each egg cell contains one X chromosome, while each sperm cell contains either exactly one X chromosome or exactly one Y chromosome. At fertilization, an egg and sperm cell and their chromosomes reunite to form the baby’s embryo.
If the sperm contains an X, the embryo will be a girl (along with the mother’s X chromosome, the baby’s fertilized egg has 2 X chromosomes), and if the sperm contains a Y chromosome, the baby will be a boy . Changing your diet during your pregnancy or suddenly stopping eating breakfast during pregnancy will never change the composition of your baby’s genes.
Answered by
Dr Anthony Liekens
Bioinformatics
Prinsstraat 13 2000 Antwerp
http://www.uantwerpen.be
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