My wife & I are trying to conceive. At the same time, I want to take diet pill XENICAL(ORLISTAT). Is this ok?

Anything that doesn’t have a long-term study behind it, or many years of FDA approval, is not wise to take during TTC. I’m sure it won’t affect the health of a baby (unless your wife was taking it, then who knows) but it might affect the sperm and then you simply wouldn’t get pregnant. I’d say stay away from it in the same way that you’d stay away from hot-tubs and other things that affect sperm. Good luck!