@Pokestardragacraft I suppose that would be something interesting to think about. Disabling them completely may be something, but then what if you actually get it later in the game without the help of this idea? I was just thinking like maybe within a certain number of generations or days, the ability to unlock these achievements could be allowed (or a better word, unlocked) again. Things like creatures with 5+ heat or cold resistance as an achievement problem maybe could be allowed to be created, however, those ones created in the editor wouldn't count (and again the allowance to get achievements based on characters could be enabled later in gameplay).
An idea following on that would be that you could select these genetics (perhaps heat body and medium tail or other heat resistant items) and when you do, a warning would pop-up, saying something like: "This creatures in-game descendants won't have the ability for X amount of generations/days to unlock genetic achievements."
One final idea, nearly the opposite of the last, would be greying out genetic items that would complete an achievement. An example of this, being for 5+ heat resistance (King of the Mountains), would be you select heat body and the editor would then grey out the other items that maybe finish the achievement (again, medium tail, Mammut foot, and other later implemented items). When you then put your mouse over these items a little line of text would appear saying something along the lines of: "This genetic item cannot be used because it would complete the ____ (in our case example, 'King of the Mountains') achievement."
Just a few ideas, I'm sure there are plenty more ways this can be worked around.