Why do I get random numbers when I am in debug mode?

Ive got a class Population with its constructor:

private Individual[] m_population;
    public Population() {
        m_population = new Individual[POP_SIZE];
        for (int i = 0; i < POP_SIZE; i++) {
            m_population[i] = new Individual();
            m_population[i].randGenes();
        }
        //some other code here
    }

Inside the Individual class I have the method for randGenes():

Random rand2 = new Random((int) DateTime.Now.Ticks & 0x0000FFFF);

        public void randGenes()
        {
            for (int i = 0; i < SIZE; ++i)
            {
                for (int j = 0; j < SIZE; j++)
                {
                    this.setGene(i, j, rand2.Next(1));
                }
            }
        }

I just need a set of 25 radnom 1s and 0s for each of the 10 individuals. But I always get the same set for each of the 10 individuals, when I fiddle even more with it I only get 0s. Its only when I enter debug mode that I get truly random numbers. I see everywhere that the new random should be created outside the method and/or the loop, which I did so I dont know what to do next?