My first grow was with two bagseeds. One was a male and the other died before it was sexed. Lol.
Here are the ratios of getting males to females.
1 seed = 50% change of male or 50% chance of female
More than 1 seed = luck of the draw....
You can get more seeds to increase the odds, but it's still just "luck." For instance, you can buy 10-regular seeds, and get 6 males, 4 females. Or you can get 1 female and 9 males. Or 10 males! Even more wild...10 females (rare). But, it's all a gamble.
There are supposedly some techniques you can use to help increase your chances of ending up with females, but I don't necessarily buy into it. I am more on the side of thinking genetics determine sex. Here's the link though if you want to give it a look...
try.http://www.1stmarijuanagrowerspage.com/how-to-improve-female-male-ratio-of-cannabis-plant.html