IS it possible to determine the sex of the child you are going to have? TALKING HEALTH with Dr. Lalick Banda

Medical Superintendent for St. Francis Mission Hospital Dr. Lalick Banda centre blue shirt

Sun, Feb 12, 2012, 3:21 PM

QUESTION: IS it possible to determine the sex of the child you are going to have?

ANSWER: SEX of a developing child is determined at the level of the chromosomes. Every human being has a total of 46 chromosomes or 23 pairs.

44 are non sex chromosomes (autosomes) and 2 are Sex chromosomes.

The sex chromosomes of a female are XX and those for a male are XY. So a male’s chromosomes should read 46XY and those of a female 46XX.

23 chromosomes of the 46 come from each parent. For example 23XX from the mother and 23XY from the father. These chromosomes are carried in the gametes (Sperms for males and eggs or ova for females).

The egg’s sex chromosomes would thus only be XX but those of a sperm can either be XX or XY. These are mixed and usually in equal proportions. The spermatozoa or sperms have certain properties. They swim and the normal swimming direction is the forward direction. They have heads which fertilise the eggs and  tails which help them to swim.

It is proved that the sperms carrying XX chromosomes swim faster or are more swift than those carrying the XY chromosomes. Further it is apparent that the sperms carrying XY chromosomes are more resistant to environmental cues than those carrying XX chromosomes.

Zambian Dr. Lalick Banda

Fertilisation takes place in the ampullae of the fallopian tubes probably because these are the widest parts. These parts are near the ovaries from which the eggs are released. After an ejaculation in the vagina, the sperms swim towards the ampullae. The lifespan of a sperm is 24 – 48 hours or 1 – 2 days. Most likely 24 hrs for those  carrying XX chromosomes and 48 hrs for those carrying the XY chromosomes.

The life span of an egg is 48 – 72 hrs or 2 – 3 days.

The chance of having a male or female child at any particular time is 50%.

Therefore at any particular time there is a 25% + 25% = 50% chance of having a male or female child.

Another thing to take in to consideration is the menstrual cycle. The menstrual cycle is ideally a 28 day cycle. It may be exactly 28 days or slightly more (30days) or less (21 days). It may be regular or irregular. It is often used as a natural, rhythm or calendar method of contraception. It can only be used for this purpose if it is regular.

Ovulation occurs 14 days before menstruation and the egg can come from either side, and menstruation occurs 14 days after ovulation, in a 28 day cycle. Both menstruation and ovulation occur slightly late or slightly early. An allowance of 3 days early or 3 days late is reasonable.

Therefore the first day of the menstrual flow can help us determine the day when the next ovulation is likely to occur. For example, if the menses start on the 6^th of November 2009, it means the last ovulation happened on the 23rd of October 2009 and the next one will happen on the 20^th of November 2009. So if sexual intercourse happens on the 4^th of November (that is earlier than the date of ovulation), the sperms carrying the XX chromosomes would have reached the ampullae of the fallopian tubes and died before the ovulation occurs. The sperms carrying the XY chromosomes would however still be alive and viable (due to their long life span) and are likely to fertilise the egg resulting in to a male child. On the other hand, if the sexual intercourse happens soon after ovulation, for example, 7^th November, the sperms carrying the XY chromosomes (which are sluggish in motion) would not have reached the ampullae. The ones carrying the XX chromosomes therefore would have reached the ampullae and fertilised the egg resulting in a female baby. What this means therefore is that having sexual intercourse just before ovulation, would lead to a male child where as having it soon after ovulation is likely to result in a female child. It must be mentioned however that, this information is not easy to understand and many women have irregular cycles. Furthermore it is more theoretical than practical for most people to abstain or delay sexual contact for the sake of sex determination. In women, the date of ovulation may be difficult to establish although there are many known methods for estimating this date.

Dr. Lalick Banda

This kind of approach requires an expert counsellor with full knowledge of the menstrual cycle and also about the properties of the spermatozoa.

Contact: lalickb@yahoo.com