Does a stepson of a first marriage have the right to contest a will if the woman had remarried?

The question is unclear as to to exactly whom the questioner is referring. It appears as if the scenario is: That their step-father died - the step-mother re-married - and they want to contest the deceased step-father's will.
The question is do you have legal "standing" to contest the will.
If they were legally adopted they MAY have 'standing' to question the will. However if the deceased made a conscious decision to omit them from his will, they probably cannot prevail.
You should consult an attorney practicing in your state for further information