In Terāpanth (Śvetāmbara Terāpanth sampradāy), this is mainly a community/custom issue, not a direct Jain-scriptural rule.

From the point of view of Jain Dharma:

• Jain āgams do not specifically talk about “second cousin marriage”.
• Jain principles focus on ahimsā, aparigraha, satya, brahmacharya, samata – not on detailed kinship rules.
• Close‑blood marriages are generally discouraged because they can:

- increase health/genetic risks for children - create family and social conflict – which disturbs śānti and spiritual progress.

From the point of view of Terāpanth community practice:

• Terāpanth traditionally does not like cousin marriages (especially first cousins) and often treats them as socially “not acceptable”, even if law may permit them.
• For second cousins, there is no single written, pan‑India Terāpanth rule.

- In some cities/families it is strongly opposed as “too close relation”. - In a few places people may be more flexible, but they usually still take approval from elders / local sabhā.

Therefore, in practice:

1. Legally (Indian law): second‑cousin marriage is usually not in the prohibited/sapinda range, but you must confirm this with a good lawyer in your state.
2. Medically: it is wise to take genetic / medical counselling before deciding.
3. Terāpanth-wise: you should treat it as sensitive and generally discouraged, and:

- speak openly with both families and senior Terāpanthi elders / local Terāpanth sabhā, - be ready to avoid it if it will create serious samaj‑virodh and long‑term tension.

So:

• Pure Jain dharma does not give a specific “allowed / not allowed” rule for second cousins.
• Typical Terāpanth community custom tends to discourage marriage among blood relatives, including cousins; second cousins are in a grey area but often not welcomed socially.