Yes. See your pediatrician or a consult with a dentist. I think you've waited long enough for teeth to sprout. they may have a genetic predisposition but wouldn't you rather make sure.
Very worried because they should have some molars. The two bottom teeth should have come through at around four to five months old. Get your girls checked out by either a dentist or clinic.
It is generally not normal for a 15 month old to have no teeth, you should have them checked out by a doctor, but possibly there could be a calcium issue.
Most babies begin teething between the ages of 3 months and 13 months. Late teething can be a symptom of poor nutrition, thyroid problems, or other health issues. You should have your daughters' pediatrician examine them.
No. you don't worry but you have to care liitle more.. Normally 7 to 12 months the teeths are coming ,,but it depends .. like you have to start feeding littlebit heavy food. If they don't have any other problems , don't worry