Michael Lohan tells TMZ he plans to be in Lindsay's kid's life, one way or another. He says he and his daughter are on good terms, and have been for years now. Ditto for his relations with his ex-wife, Dina, who's also planning to be involved as a grandma.

We're told the pregnancy has brought the Lohans closer as a family unit, and they're all on the same page in terms of introducing the child to extended relatives ... like grandpa Mike and grammy Dina.

As for logistics, Mike says he doesn't know where Lindsay will give birth, but he assumes it'll be in Dubai ... where she lives with her husband, Bader Shammas. If that's the case, ML says he probably won't make the birth in person ... but he's excited to meet his grandkid shortly thereafter.

Now, in terms of gender -- something Lindsay has yet to announce -- Mike says he knows what it is, but can't disclose it at this point. He doesn't care if it's a boy or girl, he says all that matters is the newborn is healthy.

When it comes to Dina ... she's equally excited, telling TMZ they're all in a good place, and over the moon. One big difference from Mike, though, is she says she'll be with Lindsay for the birth.

We're told this has been a long time coming for Lindsay, who Dina says always wanted to be a mom ... and who she believes will do a rock star job at it. DL says Lindsay told her the news quite a while ago, and is already working on the nursery.

She wouldn't give up whether it's pink or blue.

As for where Lindsay and Bader plan to raise their child ... Dina says they'll split time between Dubai and NY -- as LiLo's main work projects will be Stateside.

One last thing ... Dina says she's already been sharing motherly advice with Lindsay, and they're more in sync than ever. She also expects she'll have more than one kid, but no timeline for baby #2. One at a time, right?