Identical Nonidentical

Nature probably intended women to conceive very soon after puberty. In primitive societies, a girl would have intercourse fairly soon after reaching sexual maturity and would probably soon get pregnant. From then onwards she was likely to oe pregnant or breastfeeding for the next 10 or 15 years, bearing between eight and twelve babies, many of whom would die. This is of course far removed from the experience of women in modern Western societies. Few women now marry until their early 20s and having children is often postponed until the early 30s in order to pursue a career or job.

Statistically, the safest age for women in Britain to have children is between the ages of 20 and 29. Providing a woman is in reasonable health, there is no reason, however, why she should not wait until her 30s before starting a family.

The groups at greatest risk are the very youngthose under 20 – and women over 40. Among the younger group, the risk is not their age, but the fact that many of them don’t accept proper medical care.

Women in dieir late 30s may also face problems, but of a different sort. A child conceived by a woman of this age will be a teenager when the mother is in her late 50s. This in itself may produce a certain amount of family strain. Nowadays, any woman has to consider all these kinds of emotional and social factors – and not just purely medical ones.

When a mother is breastfeeding her baby, she will not usually produce any eggs. (But this is a reliable means of birth control.) Once breast-feeding stops, egg production is likely to resume six to ten weeks later. If planning another pregnancy, the ideal interval between each one depends very much on the background of the mother, her age, the size of her existing family and what domestic help she has.

For most women there is no serious medical risk in a series of pregnancies in quick succession. Problems when they do occur tend to come later, when the mother has to cope with satisfying the demands of two babies. As a general rule, it makes life easier if a woman does not have to carry two children at once; leaving an interval of between 20 to 24 months before the birth of the next baby means the previous child will be toddling or walking. A lot depends on circumstances, however, and an older woman may want to have another child sooner than this.