SQL transaction: Delete between two selects possible?

I have two SELECT statements within a transaction (repeatable read) Select @firstItem =id from myTable Where .... --Do some more magic, so I can't concat the the two queries!!!! and Select * from myTable where parent=@firstItem Is it possible that the children (second query) of the parent(first query) are deleted (from another transaction) after the initial/first select? How can I prevent this with locks?