There are two ways to look at the question, is there sperm in pre cum?
The first way is, is there sperm in pre cum when it is produced? The answer to this question is no. The Cowpers glands that produce pre cum, do not produce sperm.
The second way to look at the question is, is there sperm in pre cum when it is discharged from the tip of the penis? This is a very different question. This is a more important question. The answer to this question is that there could be. There can be sperm left over in the urethra from an earlier event. In this case, pre cum can pick up motile sperm and transfer it to a woman.
This is not uncommon. Trawl any one of the many pregnancy forums and you will find mothers who have had a baby from pre cum. When a man urinates he will flush out virtually all of the left over sperm, but it is possible that some are missed, and will remain in the urethra.
The technique of withdrawal as a form of birth control (coitus interruptus) is not 100% effective. Men do not know they are leaking pre cum unless they look. There is no associated feeling like there is with ejaculation, to tell a man that he is producing pre cum.
The answer is clear. If you are not trying to get pregnant, then you must take precautions. A condom can protect you from accidentally getting pregnant from pre cum. It will also protect you from becoming infected with an STD, which can also be transferred by pre cum.
So, is there sperm in pre cum?
The next time you hear anyone ask “is there sperm in pre cum?” you can tell them that there is a very definite possibility.