Temporary would be a short time frame usually under 1 year however it must also be in connection with a specific infertility diagnosis. So if you are just freezing your eggs now because it is not convenient to have kids right now that would not be deductible.
However if you are actively trying to have children and say you harvest 12 eggs right now but you can only implant 4 so you choose to freeze them incase the first round of implantations doesn't work then that is temporary.