I normally stay away from threads like this so that I don’t offend anyone. If anyone does take offence please forgive me retroactively.
A teacher of mine in high school once told us that everyone in the world is discriminated against one way or another. The example he gave regarding himself was that he wasn’t allowed to be a fighter pilot in the U.S.A.F. because he was over 6’6″ and couldn’t fit into the cockpit!
Growing up my parents always taught us to have the utmost respect for Baalei Teshuva. In my fathers words- “They are on a level that we can’t even come close to”. My kids got to see this first hand over this past three day Yom Tov when my parents saved the best food and nicest China and cutlery for the seuda where we had guests who were Baalei Teshuva.
When my brothers and I were dating my parents politely told shadchanim that they would only consider girls whose ancestors have always been frum- the reason being that a kohain can not marry a challal and if he does his children can not do the avodah and are not considered kohanim.
Take a simple case where a non-frum couple got divorced and she got remarried to a kohain. Their children are challalim and can not marry kohanim. (And this is in the case where we’re assuming that the divorce was done properly- think about what the parameters change to if it wasn’t done properly!)
Although this may be very rare, I do know of one family where this happened and their children are not kohanim.
There are many silly things out there but I agree with my parents for taking this seriously.