DNA analysis of Ex Muslim Movement

In the last few years, this Ex-Muslim movement has gained a lot of strength in America, Britain and European countries. Muslims are rapidly moving away from Islam. Are these ex-Muslims now adopting Christianity or Hinduism or Buddhism? Barring isolated cases, this is not so. Most of these Muslims are developing their own 'Ex-Muslim Society'. That is, instead of converting to another religion, they are preferring to call themselves 'former Muslims'.