The World's population is an ever changing factor, throughout time we have seen the shifts in family size, fertility rates, birth/death rates child mortality etc, and these changing factors are having a massive impact on today’s population.

The first key statistic to look at when examining family size, is birth trends and fertility rate. Chamberlain and Gill showed in a 2005 study that the total amount of live births per year has fallen since 1900, from 1.1 million to a figure around 700,000 in the year 2000. This figure simply means that there are less and less babies being born, this decrease is even more impressive when you consider that the adult population is much larger than it was in 1900. As this statistic doesn't take into account population inflation, it is important to look at a relative measurement, for this we will use fertility rate (the number of live births a woman has during her fertile years). This statistic also shows, birth rate and family size has decreased, in 1900 it was at 3, meaning that on average a woman would give birth to three children, however today, it has fallen to a figure around 1.8, telling us that most women are having one or two children, inferring that not only is the birth rate declining, the family size is too. But why?

There are several reasons for a decline in birth rate, the first one to be explained is a change in the role of women. The 20th century was a great turning point for female rights, education and influence; from the suffragettes, to the first female Prime Minister, and in more recent decades greater control over conception, this empowerment of women leads to lower birth rates, as they are "allowed" to focus on careers