The Attack IVs determined your Pokemon's gender in 2nd gen (this is no longer the case).
If the ratio of male/female for a Pokemon specie is 50/50, then IVs 0-7 made a female while IVs 8-15 made a male
If the ratio of male/female was 87.5/12.5, then IVs 0-1 made females, while IVs 2-15 made males.
If the ratio of male to female was 75/25, then IVs 0-3 made females, while IVs 4-15 made males.
I hope you are starting to see the pattern here.