Given that the year you're looking at is 2010, if you were 20, you would be born in 1990.
1990
If you are now (2010) 20 years old then you were born in 1990.
If they have already turned 19 this year (2010) they were born in 1991, if they will be 20 sometime this year they were born in 1990.
If you have had a birthday this year, you are 21. If not, you are 20.
If you are 20 in 2017, then you were born in 1997.
Right now, it is 2013, so if you are 20 years old, you were born in 1992 or 1993. In general, if a person is 20 years old, that means that they were born in the year (this year minus 20) or (this year minus 21).
Given that the year you're looking at is 2010, if you were 20, you would be born in 1990.
1990
2001 is the birth year for 20 yr olds the year of 2021!
2001
If you are now (2010) 20 years old then you were born in 1990.
1990
A person turning 20 in 2014 was born in 1994.
If they have already turned 19 this year (2010) they were born in 1991, if they will be 20 sometime this year they were born in 1990.
Heron of Alexandria was born in the year 20
He was born March 20, 1928.