I feel the same way about Animals as I do with Kids.
The big difference between and older child/spouse vs an animal or a young child, is the difference in their understanding of what could happen to them in a worse case scenario.
If they are capable of fully understanding that they can be crippled or killed and able to make the choice for themselves = fine.
I for one would never want the responsability of making that choice for another human being or animal that can not understand the risks.
I love my Dogs/cat too much to even think about what could happen to them in a M.C. accident (taking them out in the car is risk enough the way all these assholes on the roads drive today).
Imagine fluffy/junior getting ejected and mutilated in an accident. (the animal/young child trusts you to make the right choices for them)
Hopefully the above response is "Mature" enough for you. Are you Mature enough to face the consequences of your choice? (food for thought and not meant to be antagonistic in any way)