sql - Storing sex (gender) in database

Question

I want to store a user's gender in a database with as little (size/performance) cost as possible.

So far, 3 scenarios come to mind

1. Int - aligned with Enum in code (1 = Male, 2 = Female, 3 = ...)
2. char(1) - Store m, f or another single character identifier
3. Bit (boolean) - is there an appropriate field name for this option?

The reason I ask is because of this answer which mentions that chars are smaller than booleans.

I should clarify that I'm using MS SQL 2008, which DOES in fact have the bit datatype.

Answer 1

There is already an ISO standard for this; no need to invent your own scheme:

http://en.wikipedia.org/wiki/ISO_5218

Per the standard, the column should be called "Sex" and the 'closest' data type would be tinyint with a CHECK constraint or lookup table as appropriate.