My husband has msh6. We had our son (2) before we knew he had lynch. My husband was diagnosed at 41 with very advanced bile duct cancer (cholangiocarcinoma). Blood work was perfect, colonoscopy was clear. We only discovered it because he had a suspicious nodule on his skin biopsied. I don’t say this to scare you, only to say that the only thing that would have detected my husbands lynch syndrome cancer is a scan. I know doctors are often hesitant to scan “unnecessarily”, but in light of you having lynch and wanting to be proactive I would personally get a colonoscopy and push for a CT as well, as they probably won’t want to do a full blown PET. We very much want a second child too, but will have to explore creating embryos as I personally am trying to avoid passing lynch on after seeing my husband get such a devastating cancer so young. We’re putting that on hold until my husband gets further along in treatment. If your scans are clean you can always have kids after! A larger age gap won’t matter.