For moral scruples you would surely have taken out the life of your eldest and would have thus committed a heinous sin and fallen into eternal perdition.
स भवान् धर्मभीरुत्वाद् ध्रुवमैष्यन्महत्तमः। नरकं घोररूपं च भ्रातुर्येष्ठस्य वै वधात्॥