Determining the sex by looking at a seed is near imposible, determining the strain is likely more impossible than that. There is some support to the idea that indica and sativa seeds can be distinguished visually, with sativas having smaller, more uniformly round seeds, and indicas having larger, more oblong seeds, often with stripes. However, few pure indicas and sativas still exist. The majority of strains have been hybridized in some way, making visual distinction difficult, and still giving no induction of actual strain.