According to a study published in the British Medical Journal, the likelihood that the baby to be born will be a child is greater the longer it takes to become pregnant.
The research was conducted with 5,283 women who wanted to become pregnant, all of them around 30 years old. Before twelve months of follow-up, nine out of ten women were pregnant, 51% of the children were children. However, 56% of those who became pregnant later. According to researchers, when the pregnancy period increases one year, the probability of being a boy increases by 4%.
The explanation can be at the speed of the sperm. In fact, spermatozoa with Y chromosome (which germinate the ovum give the boy) are faster than those with X chromosome (which give girl). Sometimes, the difficulty of a woman to become pregnant is because the mouth mucus of the utero is usually more viscous than normal, and it is possible that in this lika it is easier to develop the sperm with Y chromosome.