Bidhya Sagar Das, 33, was wanted by police in relation to a “domestic incident” at a flat in Wilberforce Road, near Finsbury Park, north London, on Saturday night.
Both toddlers were found at the flat with critical injuries and were rushed to an east London hospital.
The boy died in the early hours of Sunday morning while the girl remains in a critical condition.
Das, of Wilberforce Road, was charged in the early hours of this morning and is set to appear in custody at Thames Magistrates Court.
More to follow…