how long is a generatain?

Answer 1

On average it is said that a generation is 30 years.

Answer 2

25 years

Answer 3

The best guess is probably in the low 30's, though the number a society's traditions consider to be a generation may vary.

Starting with a dictionary definition:

A generation is "the average interval of time between the birth of parents and the birth of their offspring."
http://www.thefreedictionary.com/dict.asp?Word=generation

Some take that as meaning from the time of birth of the parents to the birth of the FIRST child. But a BETTER measure is from the parents' birth to the MIDDLE of the child-bearing period.

Also note that the average age for a generation from the MALE (father's) side is generally longer, in fact, significantly longer than the FEMALE, so you can either average the two or focus on one.

An article in the American Journal of Physical Anthropology estimated the 'human generation interval' across cultures as 31-32 for males 25-28 for females.
http://dienekes.blogspot.com/2005/04/human-generation-length-male-31-32.html

An article in American Journal of Human Genetics 66:651-658, 2000 arrived at an "Intergenerational Interval" of 34.4 years for men
http://genforum.genealogy.com/dna/messages/129.html

Similarly, Jewish teaching defines a generation as "the average male age at marriage, plus one year before child-bearing begins, plus half the average number of years during which fecundity lasts." (This article places the number for the Jewish population at 30 yrs, for the general population at 36 years.)
http://www.jewishencyclopedia.com/view.jsp?artid=136&letter=G

Now of course, when people use the word "generation" they are not seeking to be that precise (and probably are unaware of the latest estimates about such things), so if they DO have any sort of number in mind it is likely to be from 25 to 35 years.

But there is also the traditional round-number of 40-years used to refer to a generation in the Bible (and perhaps reflected in the popular expression "Life begins at forty").
http://en.wikipedia.org/wiki/40_(number)#In_religion (includes other uses of 40 as a round-number)

(Some claim that a biblical generation is 70-years, but that number is more accurately described as a traditional LIFE-SPAN.)

Answer 4

a generation is the amount of time between the average birth and breeding age, and in humans is around 25 years. some bacterial generations are 20 minutes which means that in a day they could totally cover the earth if limiting factors did not inhibit growth.

Answer 5

30 years is usually used as a generation as it has been established as being the average age gap between grandfather, father, son and grandson. Allow 3 generations per century.

Consider my own numbers.2001, 1969, 1944, 1909, 1875

Answer 6

If you mean "generation" then its the time between birth and that individual reproducing. The average across that culture is then taken as a mean.
The average in the Western world is taken as roughly twenty-five years. Four generations to a century, possibly five in earlier ones.

Answer 7

40 years

Answer 8

If you mean a gereration, there is no set length. It's a group of people rather than a length of time. People of the same gereration are those born around the same time, so you'd say the children at school with you were the same gereation, or maybe all your grandparents are the same generation.

Answer 9

A generation is merely the length of time, on average, which it takes to produce the next generation. In the UK, a human generation is taken to be about 30 years, in Bagladesh it might be less. If one is talking of non-humans, think in terms of time to become sexually active + gestation time. About six weeks probably, for mice, less for flies!

Answer 10

about 25 years.