Investment properties before primary residence?

[Matthew Battistini]

I know this subject has been beaten to death previously, as I've read several threads on this exact subject. However I have a novel question I've never seen answered regarding buying investment properties before purchasing your first primary residence. My fiance is in dental school for a couple of more years, so we're just now to maintain flexibility until we know where we are going to settle. I'd love to start buying up investment properties, with a goal of two a year for the next few years.

My main concern is this: if I finance these investment properties with conventional mortgages, could I eventually disqualify myself for a mortgage on my primary residence due to increasing debt to income ratio? Currently I have zero debt and have enough liquidity to lock down a pair of SFH rentals this year.

Are there any other major reasons I'm overlooking by buying investments before a PR?