Seeds in gerimanition

Good day all,Seeds,now you can buy feminized seeds but I’m growing from one stran I have had now for around 15 years I let a cople of my stock go to seed for the next year, now I germantion them indoors start the plants indoors and transplant outside in the spring,i have been determining the sex of the plant by the way the seeds cracks open,now if it cracks on ths side its 90%shure its male,but if it comes from the tip of the seed its a female