If permanent teeth are erupting and milk teeth are still in place then you should go to dentist and get those milk teeth removed as soon as possible otherwise the permanent teth will get misaligned in the jaw. Gap between teeth can sometime be normal as it is a transition phase between deciduous rendition and permanent rendition and jaw bones are growing.

Its pretty normal during transition phase , as in from milk to permanent! Don’t panic!! Seek a good orthodontist consultation

As you said your son age is 7years Upper front permanent tooth will start to erupt at this age, if the deciduous teeth  (milk teeth) retains when the permanent teeth are erupting, it might cause crowding or mal alignment, so take your child to your dentist and get an appropriate treatment done at right time. Keep smiling

May be your son has retained front teeth which needs to be removed don't worry take him to dentist near by or you can come to my clinic where we are doing tooth removal with lasers Only clinic in Bangalore to have dental hard tissue lasers imported from USA You can visit my clinic

It happens in kids and they might need removal of retained milk teeth.