One of the interesting tidbits I picked up last week while on a business trip to Seoul was that Koreans traditionally start counting their age from one at birth. So say if you born on November 16th in the year 2000, you would be thirteen instead of twelve. The way it was explained to me was that they counted the time you spent in your mother's womb.
The official explanation of their version of East Asian age reckoning explains it in different terms:
Koreans generally refer to their age in units called sal (살), using Korean numerals in ordinal form. Thus, a person is one sal during the first calendar year of life, and ten sal during the tenth calendar year.
The 100th-day anniversary of a baby is called baegil (백일), which literally means "a hundred days" in Korean, and is given a special celebration, marking the survival of what was once a period of high infant mortality. The first anniversary of birth named dol (돌) is likewise celebrated, and given even greater significance. Koreans celebrate their birthdays, even though every Korean gains one 'sal' on New Year's Day.
Because the first year comes at birth and the second on the first day of the lunar New Year, a child born, for example, on December 29 (of the lunar calendar) will reach two years of age on Seolnal (Korean New Year), when they are only days old in western reckoning.
In modern Korea the traditional system is most often used. The international age system is referred to as "man-nai" (만나이) in which "man" (만) means "full" or "actual", and "nai" meaning "age". For example, man yeol sal means "full ten years", or "ten years old" in English. The Korean word dol means "years elapsed", identical to the English "years old", but is only used to refer to the first few birthdays. Cheotdol or simply dol refers to the first Western-equivalent birthday, dudol refers to the second, and so on.
As you might expect from such an outlook, South Korea has pretty strict laws against abortion on demand, although regrettably in practice they are apparently rarely enforced.