Spawn with rotation of 90 on x axis.

I have the following line spawning an item into my editor view when u click my editor button. The problems is that it is spawning with the wrong rotation on the x axis, I would like to change it so it spawns with a 90 roatation on the x axis. Here is the code using for spawning. I know that Quaternion.identiity is what has to be changed just can not find what to, to make this work.

 Instantiate(prefab, spawnPoint, Quaternion.identity);