There were many changes affecting families during the first few decades of the 20th century: the implementation of child labour laws, mandatory school attendance until age 16, and migration to urban areas contributed to a decrease in the size of families and households. The effect of the First World War left many Canadian families without fathers, brothers, sons and husbands.
There were 1.8 million Census families.
During most of the 1930s, the era of the Great Depression, women had fewer than three children, on average. Marriage and fertility rates fell as people may have been less able to take on additional financial or social responsibilities. The proportion of lone parent families reached a level that would not be surpassed until 1996.
Canada entered the Second World War in 1939 and women temporarily joined the labour force, many of them working in industries from which they had been excluded previously, including manufacturing. Following the war, there were higher divorce and remarriage rates as some hastily formed pre-war marriages were dissolved and war widows married again.
The period from 1946 to 1965, known as the 'baby-boom', was characterized by a high proportion of married persons, a younger age at marriage, and larger families. In 1959, women had nearly 3.9 children each, on average.
The birth control pill became available in the early 1960s, but contraception was not legalized until 1969. The introduction of the Divorce Act in 1968 broadened the grounds for obtaining a divorce to include “no fault” divorce following a separation of at least three years.
1971 marked the last census year that fertility was at replacement level, meaning that women had, on average, 2.1 children each. Also at this time, the majority of lone parents were no longer widows, as divorce became more common.
Counts of common-law couples were available for the first time in the 1981 Census. In 1986, the Divorce Act was amended to reduce the separation for “no fault” divorce to at least one year, and 1987 saw a record high divorce rate.
About one in 10 couples with children were step families in 1995, comprised of at least one child from a previous relationship. In 1996, about 2.1 million Canadians cared for senior family members or friends with a long-term physical or health limitation.
In 2001, changes to the Employment Insurance Act extended the duration of parental leave, and the 2004 Compassionate Care Benefits allowed persons time to tend to gravely ill family members. Same-sex marriage became legal across Canada in Canada in 2005, and these couples were first enumerated in the 2006 Census.