In Jainism, it is believed that some Tirthankaras are related as father and son in their various lifetimes. The most notable example is that of Lord Rishabhanatha (Adinath), the first Tirthankara, and his son Lord Bharata Chakravarti.

However, in the context of Tirthankaras directly as father and son, Jain scriptures mention that Lord Rishabhanatha (Adinath) was the father of Lord Bharata Chakravarti and Lord Bahubali, but neither Bharata nor Bahubali became Tirthankaras.

In the current time cycle (Avasarpini), according to Jain tradition, there is no direct instance where both a father and his son became Tirthankaras within the same cycle. All 24 Tirthankaras of the current cycle were born in different families, though many belonged to the Ikshvaku dynasty.

However, Jain texts do mention that in the future Utsarpini era (the ascending half of the time cycle), there will be instances where both father and son will become Tirthankaras. But for the current known history and scripture, there is no pair of father and son who have both become Tirthankaras in the same cycle.

Summary: Currently, in the present Avasarpini, there are no father-son pairs who both became Tirthankaras. In future cycles (Utsarpini), Jain texts mention there will be such pairs.