I have what I think is genetic double chin as my dad had the same face structure. What can I do? (Photos)

It is difficult to tell from your photos how much of the issue is submental fat and how much is skin laxity. My guess is that you would benefit from a combination of liposuction to remove the fat and ThermiTight to firm up the skin under the chin and on the neck. These treatments can be performed at the same time, or you can have the liposuction first and schedule the ThermiTight procedure after you have healed from lipo. Liposuction uses micro cannulas to remove unwanted fat, leaving little or no scarring behind. ThermiTight delivers radiofrequency heating deep into the dermal structure via tiny probes, which triggers additional collagen and firms the skin from the inside out. I advise you to schedule a consultation with an experienced, board-certified dermatologist for a full assessment and treatment recommendations. 

FaceTite can internally tighten the skin in the lower face and neck. After all the skin has been heated and contracted, we shape the neck with liposuction to give definition and remove stubborn pockets of fat. In one quick treatment, we can tighten skin, remove fat, and contour the lower face, jawline, and jowls with only a weekend of downtime. Keep in mind that combination approaches will give you a more significant improvement as opposed to a single procedure. I recommend getting a consultation with a board-certified cosmetic dermatologist and facial sculpting expert. Best, Dr. Emer

FaceTite is a relatively new surgical technique designed to reduce skin laxity on the face and neck.  Traditionally, skin tightening was previously achieved through more invasive procedures, such as a facelift or a neck lift. FaceTite utilizes minimally invasive radio-frequency energy to smooth and tighten skin.
Patients should not expect tightening like that of an excisional surgical result (i.e. a face lift or a lower face and neck lift).The direct removal of skin will always produce a tighter result, 

You have two options.1.  Thermitight tightening of the skin of the neck.2.Lower face and neck lift.Based on the photographs she do not have a lot of jowl formation and other areas of loose skin.That makes show good candidate for Thermitight.

 Much more information is needed such as a thorough in-person examination to determine the skin tone in your neck. The skin tone itself will determine which procedure to perform.  If there is loose and inelastic skin in the neck, a lower face and neck lift is going to be required to tighten that skin. If your skin tone is acceptable, then a neck lift would be performed which includes fat removal  above and below the platysma muscle, in addition to a platysma-plasty. You most likely have significant fat deposits above and below the  platysma muscle based on the photographs.

You appear in the images to have laxity as well as fullness under the chin. Liposuction alone is quite simple and effective but must be combined with a necklift when there is lax tissue to avoid sagging skin. The surgeon will discuss this with you but always consider the "after" look and discuss examples.