New varieties, such as Amarillo, are created through pollination of female hops, and a whole lot of mass planting and selection. Luther Burbank did similar things with potatoes, IIRC.
Without a full genetic/ breeding lesson, it's hard to explain the combinations of hops genes and the resultant possibilities in the next generation. Suffice it to say that there will be a lot of variation in the next generation and you may be lucky enough to find a superior variety.
However, if you want production (i.e. hop weight and consistent flavour/bitterness) you should stick to the clones (cuttings or rhizomes).
Some English hops were traditionally cultivated with seeds, but like their cousin, Cannabis, the seedless product contains more usable product per weight of flowers, which is perceived as better value in the market.
Darren, I think you were looking for the Spanish word sinsemilla. The prefix "sin" means "without", and "semilla" (pronounced sem-ee-yah) is "seed". Consemilla, on the other hand, is "with seed". This is not specific to any particular plant type, but was adopted widely for the illicit weed.
So, I read a lot.
Seth