I am 18 years of age, passed a kidney stone and my urologist has suggested a ct scan. is it safe, due to the radiation near my reproductive organs?

Risk vs. benefit.: The radiation from cts do pose a small risk for the development of future cancer. A ct for stones generally has a lower radiation dose (~10msv) , which puts the estimated risk at 1 in 5000. But this must be weighed against the benefit of visualizing stones & preventing the complications of blocked kidneys. There's no evidence that this dose impacts fertility & groin shields can be used.

See below: To put it in perspective:CT of abdomen and pelvis will give about 1000 millirems. This is the ame amount received by a person living in a high altitude city such as Denver in a whole year,with biological adverse effects. So,it's OK .