Genetics is the study of heredity. Every aspect of physical appearance, emotion, character and intellect is inherited from our parents and indelibly recorded in every cell in our body in the genes that are individually characteristic of every person. They record everything in the minutest detail from the size of our ears to our ability to be a great pianist.
Genes are a miracle of nature. They form an incredibly complex computer that is built into every cell and are made up of a chemical combination of protein and nucleic acid which is able to store and classify the most complicated information. The genes are stored within the chromosomes each of which contains many thousands of genes. The chromosomes themselves are so small that they are only just visible when enlarged by a very powerful microscope.
The newly fertilized egg has 23 pairs of chromosomes of which half come from the mother and half from the father, thus creating a new individual with his own particular blueprint of genes which every cell in his body will contain for the whole of his life. In a woman each pair in the 23 sets of chromosomes is identical but in the male one pair is different and it is on this particular pair of chromosomes that the whole differentiation of sex depends. When you realize that all the differences between male and female are the result of the information stored in one pair-of chromosomes, you can only imagine the amount of information stored in the remaining 22 pairs.
The genes and chromosomes are responsible for the growth and development of the baby in the uterus and throughout his childhood. They will direct his development into adult life and even into old age, making him in many respects similar to his parents but also giving him a particular combination which renders him a unique individual.
The sayings ‘like mother, like daughter’ and ‘like father, like son’ are 50 per cent correct. For every child has 50 per cent of his genes from one parent and 50 per cent from the other. Brothers and sisters on an average have half of their genes alike and may grow to be very similar, or external influences and environment may make them develop into very dissimilar people. Twins on the other hand are very special. Identical twins, who come from the same egg and the same sperm, have exactly the same genes and any differences that develop between them are due to external environment and influence. Dissimilar twins who develop simultaneously from two separate ova and two separate sperms are no more alike than any other two brothers or sisters from the same parents.
The genes in the chromosomes determine those factors such as blood groups which cannot be altered by external influence or environment, and as such they may be used in determining the possible parents of a particular child. Similarly, eye colour is unaffected by outside influences, so that parents who both have blue eyes can be almost certain of having blue-eyed children, but if they both have brown eyes then they have a small chance of having a child with blue eyes. If one parent has blue eyes and the other has brown eyes then the chances of the children having blue eyes are 50-50.
Build and personality are also inherited factors, although both of these are subject to a great deal of influence by external environment. At the end of the scale is the long, lean, quiet, nervous type of person, while at the other end is the short, square, cheerful, sociable person. While talking of build it is interesting to note that the eventual weight of a person is in no way related to his size or length at birth. Height is determined by genes (again subject to external environment) so that eventual height and build are in no way related to the length or weight of the baby at birth.
Intelligence and the ability to reason, which are supposed to make man unique among the animals on earth, are certainly inherited assets. There are many examples of the way in which brilliant brains will run through brilliant families, but it is equally true that intelligence requires training, stimulation, encouragement and opportunity to develop. Intelligence is often something quiescent or latent and requires quite a lot of encouragement to develop to its fullest possible extent, and this is where parents, relatives and schoolteachers play a most important part, for it is certainly true with each and every one of us that we never really achieve our full intellectual capacity. It is also true that the more care and attention you pay to your own child’s intelligence and character, then the greater will be his intellectual ability.
What about physical beauty?
There is no gene for beauty alone since beauty is made up of many things and in any event is only ‘in the eye of the beholder’. But it is undoubtedly true that beautiful women will probably be blessed with beautiful daughters and that handsome men will frequently have handsome sons.
How then can you know what your baby will be like ?
The simple answer is that you can’t. He will be a mixture of you and your husband and yet will be a unique individual. He will inherit some of your characteristics and some of your husband’s and the combination will create an entirely new person, both physically and mentally. If there are no inherited abnormalities or diseases in your family or that of your husband, your baby stands more than a 99 per cent chance of being absolutely normal. If there are inherited diseases or abnormalities.
How can you affect your baby’s development ?
On the one hand there is very little you can do to affect the development of your baby while he is still in the uterus; on the other hand, there is a great deal that you can do to help him develop normally. A baby will develop properly and grow normally provided the pregnancy is normal. You should only take those drugs that have been prescribed by your doctor or by the clinic. You should keep away from people who have infectious diseases. You should attend the antenatal clinic and do as you are instructed. You should avoid gaining too much weight and you should report abnormal symptoms as detailed in Chapter Hi You should have as much rest as possible and certainly avoid becoming overtired. Modern antenatal care is designed to ensure that you will have a normal baby and that you yourself will be fit and healthy afterwards, and if you obey these principles you can rest assured that nothing will harm your baby.