Interesting perspectives. My two cents. I don’t believe that CD per se is genetic. From my limited research and looking at my son’s family history it is just the predisposition to autoimmunity that is genetic not the actual disease. My son has CD, and he was diagnosed and showed symptoms before his dad. His dad’s CD developed about a year after our son was diagnosed when he stopped smoking. They have other autoimmunity on their side such as Rheumatoid Arthritis and MS. Always reminds me of that saying I read often "genetics loads the gun, but the environment pulls the trigger”. Would I have children knowing that they will / might / have develop an autoimmunity disease ? Hell yes. This disease as horrible as it is, and as debilitating as it is DOES NOT define him. It makes him stronger. He is going to do important things with his life still (already has big plans).
There is a genetic factor to IBD (UC and CD) I've been sick with CD for 25 yrs and have had a lot of time to research plus being a member of the CCFC helped since they send literature with updates and info on IBD....My mom had UC but she developed her UC a couple of yrs after I got sick with CD first (because her UC was triggered later than mine) the problem is, they still don't understand how it gets passed down like they do with MS for example, which they do know how it passes. I am the youngest in my family and so far the only one that has developed IBD out of all my siblings, but I have 2 nieces that have it as well (and I have a ton of nieces and nephews).
Research has found many genes that are linked specifically to IBD as well, but it's not clear why exactly it gets triggered for some of us but not all. IBD (CD, UC) can most definitely can be inherited, doesn't mean it always will be and there's no way to determine if you will pass it on or have it passed on to you from you parent(s)/family members...There is actually a -10 to 15% increased risk of developing IBD if one parent has an IBD and the % goes higher if both your parents have IBD.
There are some cases in which almost all family members have IBD, there seems to be a genetic factor for many IBDers but not necessarily all (according to science) but since how it can be passed is still unknown, that's not to say that any blood relative that has an IBD could be enough of a link for it to be passed (not just if the/a parent(s) have it). A study done with twins where one has IBD shows that the other twin will have a 40-60% chance of also developing it.
Ever wonder how many past relatives you've had they could very well have ended up with an IBD had it been triggered before they passed away? I'm sure it happens.
One last thing, for crohn's there is a gene located on chromosome 6 that is "scratched" which causes it to malfunction allowing toxins in rather than keeping them out and it is linked specifically to crohn's (refer to Dr. Kathy Siminovitch).
The following is from WebMD;
"Is genetics connected to Crohn's disease?
Brothers, sisters, children, and parents of persons with IBD, including Crohn's disease, are slightly more likely to develop the disease themselves. about
10% to 20% of people with Crohn's disease have at least one other family member who also has the disease. The condition is more common in certain ethnic groups, such as Jews, and is more prevalent in Caucasians.
Is this tendency toward IBD and Crohn's disease passed genetically? Scientists have identified a gene associated with Crohn's disease. This gene helps the body decide how to react to certain microbes. If the gene has changed or mutated in some way, your body's reaction to microbes may also be different from the normal reaction. Over time, IBD or Crohn's disease may develop. People with Crohn's disease have this mutated gene twice as often as people who do not have the disease."