Turns out that there is an ISO standard for sex. Man is 1 and woman is 2. But why man precedes woman? The standard explicitly states that no significance is to be placed on the fact that male is encoded as 1 and female as 2. The encoding merely reflects existing practice in the countries that initiated this standard.
More information at ISO.
International standard ISO 5218 defines a representation of human sexes through a language-neutral single-digit code. It can be used in information systems such as database applications. (Source: Wikipedia)
The four codes specified in ISO 5218 are:
- 0 = not known,
- 1 = male,
- 2 = female,
- 9 = not applicable.