An ATV can come in many engine sizes, so when considering the purchase of a vehicle for a family member, their ability to handle the power needs to be addressed. Giving a younger member of the family an ATV with more power then they can handle is a mistake, and can be very dangerous. If the operator is under the age of 14 then it is recommended to keep engine power under 70cc. But if they are adults, then whatever engine size they are comfortable handling, and one that can carry the designated load, will be fine.