Make rules of you must have two gladiators, male and female, both with thier freedom papers and you can choose to make them breed.
If you make them breed you will still have the option of buying either of them back for the same price as was always, however, these two will offer you thier first born for 2 million gold.
If you choose to buy their first born than these two will take the money and dissappear never to be seen again, meaning you can no longer buy either of these fighters back ever again, but you do have their first born. You just gave them 2 million gold after giving them freedom papers, trust me they are off hiding somewhere making more baby's happily.And just so no one cheezes this rue make sure to say, of course if you buy one of them of these fighters back to fight for you, you can no longer buy the other parent back, or the child as the other parent runs away with his/her child. So if you want to buy that child you can't buy his/her parent/parents.
The first born stats will be between the mom and dads, such as dad has str of 85, mom has str of 73, the kids str will be no lower than 73, and no higher than 85, anywhere in between.
Maybe make two off stat so there is always one lower than the lowest, and one higher than the highest.
Anyways I think it would be interesting to do something simular to this.
And I'm not sure about what to make out of things, first idea would come if dad is human and mom is elaar, give the baby extra attack bonus power, armour pen, crit effects resistance, and less health, but with this idea also probably ensues some very unfair ideas.
If that was the case the first thing that would come to mind for me is I would breed a Trug with a snivler, trug gets extra health, snivler gets less health, so that would cancel, Snivler gets fast inititive, trug gets slow inititive, so that would cancel, so my character would get inflict extra bleeding and bleeding resistance with no penalty. Of course anyone who makes a baby is going to make it out of two premier glads for better stats, and I would make myne a theatrics glad.
A dundar mixed with a trug might be interesting, might as well made it a two handed gladiator while your at it and have your lowest stat be agility. :P