I partially agree with what the Doctor says, but I also take it a step further. Iam one who believes that many fetishes start in childhood, and then grow.
When I was younger, I used to walk on my toes on my left foot due to a short tendon that required surgery and was corrected at age 9. Until and just after the surgery, the adults in my life were so concerned about my toe walking, and I was constantly in therapy having my feet and toes pulled at, that I think it may have developed at least partially from that.
Then, also in early childhood, I also developed a habit of smelling feet. Every time I had a new babysitter in childhood, I would ask to smell her feet, even getting away with it with one of my mom's friends who was an airline stewardess when I was about 8. This is where my foot fetish developed. I have liked feet since I was about 5, and still do today.
As for tickling, that came much later. It started in the late 80s and early 90s when I began reading articles in Leg magazines, and then developed from there into a "preference" or "fetish" through letters to my late pen pal Don Fraser, whom I corresponded with from 1997 until his death in July, 2002. Gradually, after I became pen pals and friends with Don, I began writing female letter pen pals letters asking them tickle questions, and when anyone responded, I would share the info with Don. It was through my friendship with Don, and the correspondence from these female letter pen pals that my tickle fetish intensified, and it has continued to do so since I joined TMF in 2002.
So, in short, for me, while my foot fetish developed in early childhood, my tickle fetish came about much later. As for how strong my fetish is, while I do admit that it excites me to see women getting tickled or bare female feet, I prefer to think of my "fetish" or "preference" as part of the greater sexual experience. While I do not think I could be with a woman who absolutely refused to let me kiss or play with her feet ever, I could probably be satisfied with foot worship as part of the sexual experience for us both, instead of tickling her into submission or playing with her toes sexually several times a day. I can control it, as long as it is not forbidden.
I think many couples have preferences or fetishes to varying degrees, and as long as both parties agree on it or are willing to compromise to please their partner, I say anything goes in a sexual relationship so long as the participants are happy and agreeable to it.
Mitch