The most likely thing here is that you’re asexual — that is, you simply have no libido or interest in sex. If your lack of interest in sex bothers you because you WANT to want sex, then it’s not a bad idea to rule out any physical or medical issues. But it is also entirely possible that you’re a healthy young man who just has no interest in sex and that’s fine. Most people interested in romantic relationships will be expecting sex to be part and parcel. Now with that being said, It is going to be important that you’re interested in to be upfront and direct about this from the beginning with the women you’re interested in dating.