I want to customize a shirt that resembles a jersey. I will not be using the team logo nor kit manufacturer name nor sponsors.

If it’s PROBABLE that an APPRECIABLE number of ORDINARILY PRUDENT potential purchasers of sports-related shirts would LIKELY be confused into falsely believing that your shirt is sold by the “kit manufacturer” or that it sponsors, endorses or is associated with your shirt, or you, then your sale of your shirt is unlawful. That’s the test for trademark infringement. Notice that NONE of the capitalized words has one specific definition – each will take on a meaning specific to the circumstances of the alleged infringement. There is, therefore, no quantifiable “percentage of resemblance” that makes one product’s sale lawful and another unlawful. Only your own attorney, in private, can evaluate your particular circumstances, apply the law to your particular facts, to determine the amount of risk [if any] you would incur should you sell your particular product. If you only make one shirt for your own personal use then no matter the outcome of that analysis you would not infringe because your shirt would never enter the stream of commerce. So, yes, it’s lawful to make one shirt displaying whatever you like and to wear that shirt in public. Good luck.

If your shirt does not use the trademark of another (e.g., a team logo, a team name, a mascot, or even a distinctive color arrangement) and if it does not use any artwork designed by another, then you should not have a problem.

No one will know or care about your own personal use. Can you imagine the NY Knicks going after a bunch of inner city kids because they created their own jerseys having no money to buy the over-inflated ones at retail? My colleague Attorney Ballard offered an excellent summary of the law. If you plan on selling these by playing off another's mark and people are buying them because of that then you are exposed...simple. If no one can reasonably identify the other's mark then you have no problem, but will they sell? Do not invest anything without talk it over with a professional first. I suggest that you consult with a lawyer in private and discuss your objectives in more detail. You can start by calling around to several for a free phone consultation, get some insights then pick the best fit to work with. Best regards, Frank Natoli-Lapin, LLC

There is no mathematical formula. That is not how the law works. Do not sell your garment, wear it for yourself, and you stand a far better chance of being legal.

Have you ever heard the kreplach joke? Here is a version of it: http://divinityisinthedetails.blogspot.com/2006... It's not a percentage question. It's more in the eye of the beholder.