British families have told of their heartbreak after learning that an IVF clinic allegedly used the wrong sperm and egg donors - leaving some parents to find out their children share no biological connection. It's the most vulnerable time in any hopeful parent's life, from complex procedures to the mental toll and eye-watering expense. But for thousands of couples across the UK, the demands of IVF are more than worth it to have a child of their own. Many travel abroad for cheaper prices,