Like most other western nations, women in Australia are having fewer children. In 1970 the average number of children that women were likely to have was 2.9. Now - around 30 years on - the number has fallen to 1.7.

This trend is reflected in our study with younger females having, and planning to have, fewer children than earlier generations of females.

In the following graph we see that women aged 65 years or over were likely to have had 3 children while women aged 18 to 24 years are planning to have 2 children only.

Although younger women may expect to have two children, the actual number of children they have is lower. This suggests that some women are not having as many children as they originally planned.

As the study follows people over time, it will enable research into the reasons for the gap between intentions and actual experience. Data from 2001 suggests one reason why women may not achieve their fertility preferences is a lesser desire for children among men. As shown in the graph below, on average, men are more likely than women to report not wanting to have any children. Young men, in particular, are much more likely to report not wanting any children, and hence the average number of desired children is less (1.8 children for young men, compared with 2.0 for young women).

A series of questions focusing on the decisions people make about whether or not to have children were included in the 2005 survey. Among the most common factors that people reported when considering having children were 'having someone to love', job security, age and life purpose. The following table shows the five most important factors by age for both men and women.

When interviewed in 2004, 4 percent of women aged 18 to 44 were pregnant.

The average age of these pregnant women was 29 years. Eleven percent of couples without children have a physical or health reason that makes it difficult for them to have children.

A feature of contemporary Australia is both the relatively high rate of marital separation and the high incidence of childbirth outside marriage. According to data from the Australian Bureau of Statistics, for example, some 32 per cent of marriages end in divorce, while almost 30 per cent of new births occur outside of marriage.

As a result, there is a relatively large number of children who reside with just one of their biological parents. The Living in Australia study shows that 28 per cent of all children aged 17 or less have another parent who does not reside with them at least half the time.

According to resident parents who live with their children, 39 per cent of the youngest children in the family (aged 17 years or less) have had no contact in the last 12 months with their other parent who lives somewhere else. Further, the proportion who never stay overnight with their other parent is higher - 56 per cent. Parent contact with the youngest child at the other households is much more variable, but averages 55 nights per year (equivalent to a weekend every fortnight). Of course, older children can be expected to have more contact with a non-resident parent.

Given these figures it should not be surprising that a large minority of respondents indicated that their child did not have enough contact with the other, non-resident, parent. Almost 40 per cent of respondents reported that the amount of contact was inadequate. The majority - 55 per cent - however believed the amount was about right. This leaves a very small proportion - just 5 per cent - who thought the amount of contact was excessive. Of some interest, among the sample of parents with young children living elsewhere, the large majority - 72 per cent - were also of the view that the amount of contact was inadequate.

First marriages

Although marriage today is not as popular as it used to be, most Australians will marry at some stage during their lifetime. What has changed dramatically over the past 50 or so years is the way that people enter into marriage.

Traditionally, a couple might enter into a lengthy engagement but almost definitely would not consider living together prior to marriage. Today things are very different - a couple is in the minority by choosing not to live together before marriage.

• Prior to the 1960s very few couples lived together before marriage.
• During the 1960s the proportion rose to about 5 per cent.
• The figure then shot up to 30 per cent by the end of the 1970s.
• By the end of the 1980s this figure was at 50 per cent.
• As we enter the 21st century the vast majority of marriages - over 70 per cent - are now preceded by a period of living together.

Second marriages

People who had re-married by the time of their 2004 interview reported that their first marriage lasted an average of 8.5 years while the average length of their second marriage was 15 years - double the average length of their first partnership.