This is a normal question asked by married couples to their doctor. Some doctors are of the opinion that is possible under certain circumstances.
The married couples are advised to follow the method described below and test it efficacy:If a spermatozoa carrying XX sex chromosome fertilizes the ovum, the egg develops into a girl child, and if spermatozoa carrying XY sex chromosome fertilizes the ovum, the egg develops in to a male child. It has now been established that the female XX chromosomes have a longer span of life than the male XY sex chromosomes when they are in the uterus or fallopian tube. However, the speed of movement of the female XX sex chromosomes is slower than that of the male XY sex chromosomes.
The male sex chromosome (XY) is endowed with the power of quicker movement. This will travel quite faster and will quickly reach the mature egg awaiting fertilization in the fallopian tube. But the life span of these male sex chromosomes (XY) in the uterus and in the fallopian tube is less. In a 28-day menstrual cycle, the ripened egg is released from the ovary and reaches the fallopian tube within next 14 days. This means that if the couples have coitus on the 12th day of a 28-day menstrual cycle, the male chromosomes (XY which contained in spermatozoa) ejected during coitus will die by the time when the mature egg reaches the fallopian tube on the 14th day. But the female sex chromosomes (XX) which are endowed with a longer life span will remain alive and will move slowly and reach the matured egg which has arrived in the fallopian tube on the 14th day (of the menstrual cycle), as a result of which the baby will be a female one. But if the coitus is had by the couple on the 14th day of the 28-day menstrual cycle, the male sex chromosomes (XY) will move faster and reach the matured egg which has just arrived in the fallopian tube on the 14th day and the result will be a male child. This arrangement of the day of coitus is applicable to a 28-day menstrual cycle of the woman. In the cases of the menstrual cycles of different durations, the day of coitus has to be adjusted in accordance with the fertile days and peak day mentioned in the ovulation method of birth control described earlier in this chapter.