No. That would be just "Jsou rodiny bez matek." - but that can have too meanings actually, it is ambiguous. It can mean both what you suggested or "They are families without mothers."
A non-ambiguous one is "Rodiny bez matek jsou." or "Existují rodiny bez matek." Both is clearly "There are families without mothers."
Czech has no articles. And the to is not even a demonstrative here. This is the "to je"/"je to" construction. The TO is the subject of the sentence. To je velký dům. To jsou velké domy. To jsem já. Jsi to ty. Jste to vy? Jsou to oni? Jsou to rodiny. To jsou rodiny. Jsou to rodiny bez matek.
There is a comedic Serbian movie about one family who run mortician bussines, 6 male generations, from great great great grandfather to 6th generation grandson, and every wife/mother has died- males outlived every female in family, it is calles " Maratonci trče počasni krug " https://youtu.be/WwonBqfddHM https://youtu.be/6fL0LhjpDgU