Marik would point out that since he wants all things to end, the last thing that he'd want is something of his to exist to carry on his line. And also that it really will not be an issue of Bakura 'letting' him do anything - the child will die whether Bakura likes it or not. Though Marik would obviously prefer to kill it before its born than after, so that it'll have less emotional distress for Bakura.
Re: Arrogance and Malepreg
Marik would point out that since he wants all things to end, the last thing that he'd want is something of his to exist to carry on his line. And also that it really will not be an issue of Bakura 'letting' him do anything - the child will die whether Bakura likes it or not. Though Marik would obviously prefer to kill it before its born than after, so that it'll have less emotional distress for Bakura.