For those of you who fear microwave radiation:
The wavelength of light that is needed to damage DNA lies in the higher energy regions of the electromagnetic spectrum, the higher end of the Ultra-violet (10 x 10^-9 m to 400 x 10^-9 m), the X-Ray (0.01 x 10^-9 to 10 x 10^-9 m), or the Gamma (< 0.02 x 10^-9 m).
Microwave light lies in the low energy region of the electromagnetic spectrum, or 1 mm to 1 m.
Furthermore, the photon energy required to break one of the chemical bonds of DNA, if we use the canonical equations relating the wavelength of light to the energy of a photon:
E = hν
where E is the energy (J, Joules which is a unit of energy), h is Plank's Constant (6.626 × 10-34 J s), and ν is the frequency (s^-1) of the wavelength of light. The frequency is also expressed in terms of the wavelength
where c is the speed of light (2.9979 x 10^8 m/s) and λ is the wavelength of light (in meters, m).
So, the energy for a photon is
E = hc/λ
Plugging in the values for the speed of light, Plank's constant, and the higher enery end of the Microwave region, or 1 mm (1 x 10^-3 m), the energy of a photon is
E = [(6.626 x 10^-34 Js)(2.9979 x 10^8 m/s)]/ (1 x 10^-3 m) = 1.986 x 10^-22 J
Similarly, the energy of a photon in the lower and upper regions of the Electromagnetic spectrum are
E = [(6.626 x 10^-34 Js)(2.9979 x 10^8 m/s)]/ (400 x 10^-9 m) = 4.966 x 10^-19 J
E = [(6.626 x 10^-34 Js)(2.9979 x 10^8 m/s)]/ (10 x 10^-9 m) = 1.986 x 10^-17 J.
The energy required to break the covalent bonds (the class of bond that exists between all of the atoms in DNA), the most common being carbon-hydrogen (C-H), carbon-carbon (C-C), and carbon-nitrogen (C-N) have bond energies 413, 348, and 308 kJ/mol, respectively ( a mol means 6.022 x 10^23 constituent particles or atoms per mol; a mol is a unit).
So, the energy in the weakest bond (in this case the carbon-nitrogen bond) is
E = (308 x 10^3 J/mol)/(6.022 x 10^23 mol^-1) = 5.115 x 10^-19 J
THEREFORE, you need to be in the Ultra-violet region of the electromagnetic spectrum.