Maryam

After rereading the Maryam there is one other part that caught my attention. On the first page Shakir states: "And surely I fear my cousins after me, and my wife is barren, therefore grant me from Thyself and heir." Later Shakir states: "She said: When shall I have a boy and no mortal has yet touched me, nor have I been unchaste?" First of all, how does he know is wife is barren if she has not been touched by any mortal? Maybe I missed something in the translation here, but it sounds like a conflict in the scripture. I also found these same scriptures in Al-E-Imran.