A baby boom is a period marked by a significant increase of birth rate. This demographic phenomenon is usually ascribed within certain geographical bounds of defined national and cultural populations. People born during these periods are often called baby boomers. The cause of baby booms involves various fertility factors. The best-known baby boom occurred in the mid-twentieth century, sometimes considered to have started after the end of the Second World War, sometimes from the late 1930s, and ending in the 1960s.
Until the 1960s, the Aboriginal population rose steadily. The child mortality rate started to decline steadily in the 1960s, due to the increased access to health care. Throughout the 1960s, the fertility rate remained high, resulting in the Aboriginal baby boom peak in 1967 - about ten years after the postwar baby boom in Canada. 
While Aboriginal fertility has remained higher than the overall Canadian birth rate, it has decreased from four times in the 1960s to one-and-a-half times today. However, demographic change was just a part of the reason for the increase in Aboriginal population in the last half of the century. 
Generation X refers to the birth rate decline after the mid-20th century baby boom. Author Douglas Coupland, who coined the term Generation X, defined it as children born 1960 and after. High unemployment and uneven income distribution welcomed Generation X, giving them little opportunity to produce the next baby boom.
In 2011, the children of baby boomers made up 27% of the total population; this category was called Generation Y, or the "baby boom echo." The fertility rate of the generations after the baby boomers dropped as a result of demographic changes such as increasing divorce and separation rates, female labour force participation, and rapid technological change. 
The echo generation's children, known as Generation Z, are people born after 1993, or after the invention of the Internet, making up over 7.3 million people in Canada born between 1993 and 2011. 
"According to the new UNICEF report, almost 2 billion babies will be born in Africa between 2015 and 2050 and the 2 main driving forces behind this surge in births and children are continued high fertility rates and rising numbers of women able to have children of their own."
By 2050, Africa is predicted to account for about 41% of all births in the world, 40% of all children under the age of five, and 37% of all children worldwide (under 18). Africa will become more crowded as its population continues to grow, considering the continent is predicted to grow from 8 people per square kilometer in 1950 to 39 in 2015, and to around 80 by the middle of the century. 
The HIV/AIDS crisis in Africa has contributed to a population boom. Aid money used for contraception has been diverted since the start of the AIDS crisis in Africa into fighting HIV, which led to far more births, than deaths from AIDS.
Africa accounted for one out of every nine births in the world in 1950. It is predicted that they will account for approximately one in every three global births by the year 2030. Africa would account for almost half of all births by the end of the century.
In Japan, the first baby boom occurred between 1947 and 1949.[note 1][note 2] The number of births in this period exceeded 2.5 million every year, bringing the total number of births to about 8 million. The 2.69 million births in 1949 are the most ever in postwar statistics.[note 3] The cohort born in this period is called the "baby boom generation" (団塊の世代, dankai no sedai, means "the generation of nodule").
A period of more than 2 million annual births from 1971 to 1974, with the number of births in 1973 peaking at 2.09 million, is referred to as the second baby boom. However, unlike the first boom, this increase in the number of births is an increase in the number of births not accompanied by an increase in the total fertility rate. The people born during this period is often called "baby boom junior" (団塊ジュニア, dankai junia, means "the juniors of the generation of nodule").
The rate of births has been declining since the second baby boom.
The term "baby boom" is often used to refer specifically to the post–World War II (1946–1964) baby boom in the United States and Europe. In the US the number of annual births exceeded 2 per 100 women (or approximately 1% of the total population size). An estimated 78.3 million Americans were born during this period.
Since the beginning of the 20th century there were several baby booms:
Israel has been in a constant baby boom since independence, with the highest fertility rate in the OECD at 3.1 children per woman. In addition to having the highest fertility rate among developed nations, it is the only developed country to have never had a sub-replacement fertility rate. Israel's baby boom began in 1947, a year before independence, when the fertility rate among the Yishuv, or Jewish population of what was then Mandatory Palestine, began to rise dramatically as a result of the aftereffects of the Holocaust and expectations of Jewish independence.
College enrollments have been on the rise as the baby boomers' children — sometimes known as the "echo boom" generation — come of age. This group, born from 1982 to 1995, is about 80 million strong.