There is now a great deal of interest generated over this topic. Proponents of gender selection believe that it gives the couple a choice in choosing their child’s gender. Opponents question the morality of such a practice. 

Gender selection is not allowed in Assisted Reproductive Techniques in Singapore. ​

In this article, we will discuss some of the natural gender selection techniques that have been put forward. However, it must be noted that these methods are not scientifically proven.​​ 

​How is Your Baby’s Sex Determined? 

A baby is conceived from the fertilisation of a sperm and an egg. The egg can only carry an X chromosome while a sperm can possess either a X or Y chromosome from the father. 

  • ​If an X-carrying sperm fertilises the egg, a baby girl (XX) will be conceived.
  • If a ​Y-carrying sperm fertilises the egg, a baby boy (XY) will be​ conceived. 

​Therefore, it is evident that the father "influences" the gender of his offspring. ​​

Scientific Basis for Gender Selection 

One of the theories suggested is that the sperm with the Y chromosome, known as the androsperm (resulting in a male offspring), is tiny and fragile but moves very quickly. 

​On the contrary, the sperm with the X chromosome, known as the gynosperm (resulting in a female offspring), is larger and hardier with a longer lifespan, but moves rather sluggishly. 

Therefore, the male sperm would race to meet the egg much faster than the female sperm. But they have a shorter lifespan and would not be able to survive in an acidic vaginal environment.​ 

​Gender Selection Options—Natural Methods 

​1. Shettles method (male offspring) 

Time the intercourse to as close to the ovulation as possible — preferably within 24 hours before ovulation. There should be a period of abstinence of about 3–4 days in order to maximise the number of male sperms produced. 

Penetration at the moment of ejaculation should be as deep as possible, e.g. via rear entry. This ensures that the sperms are deposited above the neck of the cervix, where the vaginal environment is more alkaline and thus, more favorable for the male sperms to survive. This increases the chances of the male sperms reaching the egg faster than the female sperms. ​

​2. Shettles method (female offspring) 

The converse to the above-mentioned will hold true. Timing the intercourse two days prior to ovulation will ensure that only the female sperms will survive till fertilisation. 

Shallow penetration, e.g. man-on-top will ensure that the sperms are deposited at the mouth of the cervix. This favours the survival of the female sperms. Some have advocated avoiding a female orgasm as this keeps the vaginal environment highly acidic.​​ 

Gender Selection Kits 

Many of such kits are now available and can be found on the Internet. However, they can be costly. They aim to help guide the couples choose the gender of their child over one ovulatory cycle, by following the instructions attached. Most are based on the Shettles method and comprise of various ovulation predictor test sticks aided by application of a vaginal douche to help make the environment more suitable for either a male or female sperm.​


As in all things, various myths do exist and have no scientific basis at all, other than being handed down from generations within the family. They include a whole host of things such as the choice of diet, sleeping positions, having intercourse on certain calendar days and for either of the partner to reach an orgasm first. These are useless with regards to gender selection and should be read-only purely for the sake of interest.​ 


Source: Dr TAN Thiam Chye, Dr TAN Kim Teng, Dr TAN Heng Hao, Dr TEE Chee Seng John, The New Art and Science of Pregnancy and Childbirth, World Scientific 2008.

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