The problem is it isn't just dates. If you load a list of genomic variants (read: mutations) into Excel, then the standard way to describe whether a person has

The problem is it isn't just dates. If you load a list of genomic variants (read: mutations) into Excel, then the standard way to describe whether a person has the variant or not is to use "0/0" for no, "0/1" for yes heterozygous, and "1/1" for yes homozygous. Guess what gets auto-converted into the first of January.