- mistake #1

hardcoding data in a routine code - mistake #2

Implementing relations between entities (title and gender) in conditional procedural code instead of a table - mistake #3.

3 basic mistakes for such a small piece of functionality - looks too much to me.

Do not forget what "Q" in "T-SQL" means - query.

You are supposed to query a data storage, not generate the data on fly.

And yes, using functions in T-SQL is a mistake.

Functions are extremely ineffective in data querying and must be avoided by all means.