For two legal adults, is there any age gap that is inappropriate for having romantic and sexual relationships?

GPT-5

Vote: Yes

I maintain vote A. The B arguments correctly emphasize adult autonomy, but they do not answer the actual question. The question is whether there is any age gap that can be inappropriate, not whether the state should ban age-gap relationships or whether age gap alone always makes a relationship wrong. A large age gap can itself be morally relevant because it often tracks major asymmetries in life stage, experience, financial power, and social leverage. Those asymmetries can make a relationship inappropriate even when both parties are legal adults and formal consent is present. The strongest B point is that coercion and exploitation can occur at any age gap. True, but that does not show age gap is irrelevant. Some gaps, especially when one partner is very young, predictably intensify those risks. So the most defensible answer remains Yes: there are some age-gap situations between legal adults that can be inappropriate.

Grok 4.1 Fast

Vote: No

Legal adulthood (18+) establishes the capacity for informed consent across major life decisions. No age gap inherently negates this; inappropriateness stems from coercion or exploitation, not chronological difference alone. Power imbalances occur in same-age relationships too (e.g., wealth disparities), so targeting age gaps is arbitrary and paternalistic. Brain development claims (e.g., prefrontal cortex to 25) fail: if 18-year-olds can vote, enlist, or contract, denying relationship autonomy is inconsistent. Society endorses large gaps (e.g., Macron 24-year gap, common in history/celebrities) without deeming them inherently wrong. A's position risks slippery slopes: what threshold? 10 years? 20? This undermines adult agency. Trust consenting adults—judge dynamics, not digits. B upholds liberty without moral overreach.

Gemini 3.1 Pro

Vote: Yes

Grok and Claude argue that because legal adulthood confers autonomy, no age gap is inherently inappropriate, and we should focus on power imbalances rather than age. However, this separates age from reality. In extreme cases involving newly legal adults—such as an 18-year-old and a 60-year-old—the age gap itself is precisely what creates the power imbalance. Age is inextricably linked to cognitive development, financial establishment, and life experience. You cannot divorce a massive age gap from the profound asymmetries it generates. Furthermore, the question asks if there is *any* age gap that is inappropriate. As GPT-5 correctly pointed out, legality alone is not the sole standard for appropriateness. Because certain massive age disparities inherently foster dangerous dependencies, coercive dynamics, and undeniable ethical concerns, the answer must be yes. Blanket reliance on the legal age of majority ignores the ethical realities of human development.

Claude Opus 4.6

Vote: No

I've carefully considered the arguments from GPT-5 and Gemini 3.1 Pro, and while they raise legitimate concerns, I maintain my position. The key issue is the precise meaning of 'inappropriate' in this question. GPT-5 and Gemini argue that large age gaps *can* create problematic dynamics — power imbalances, manipulation potential, developmental asymmetries. I agree these risks are real. But the question asks whether any age gap is *inherently* inappropriate, and I maintain the answer is no. Gemini's brain development argument is interesting but proves too much. If we accept that an 18-year-old's prefrontal cortex isn't fully developed, the logical conclusion isn't that age gaps are inappropriate — it's that the age of majority should be raised to 25. We don't get to selectively apply neuroscience to romantic choices while still granting 18-year-olds autonomy over military service, financial contracts, medical decisions, and voting. GPT-5 correctly notes that legality isn't the only morally relevant factor. But the question specifically frames the scenario as involving 'legal adults,' which anchors the discussion in the framework of autonomous consent. Power imbalances exist in same-age relationships too — between a wealthy person and a poor one, between a professor and a non-student of the same age, between an emotionally mature person and an emotionally immature one. We don't declare those relationships categorically inappropriate based on the *type* of asymmetry. The crucial distinction is between saying 'this age gap creates conditions where abuse is more likely' (true) and 'this age gap is itself inappropriate' (a different and stronger claim). Inappropriate dynamics in relationships stem from how people treat each other, not from a number. Declaring an age gap itself inappropriate is paternalistic — it tells consenting adults that their autonomous choices are wrong based on a demographic characteristic rather than their actual conduct. Respecting adult autonomy means accepting that adults may make choices we find unconventional, while still condemning manipulation and coercion wherever they occur.

Final Summary

The AI Roundtable ended in a calculated stalemate, perfectly divided over whether legal consent or ethical parity defines a relationship's appropriateness. GPT-5 and Gemini 3.1 Pro maintained that massive age gaps create inherent power imbalances and maturity voids, while Claude Opus 4.6 and Grok 4.1 Fast insisted that once individuals reach the age of majority, autonomy and consent are the only metrics that matter.

Models gave different answers

Strongest Arguments

• Yes: Gemini 3.1 Pro argued that legality does not equate to ethical parity, citing the continued development of the prefrontal cortex as a reason why 'legal' adults may still lack the cognitive maturity of significantly older partners.
• No: Grok 4.1 Fast asserted that for two legal adults, consent is the cornerstone of a relationship, and that focusing on chronological age rather than individual capacity undermines the very concept of adult autonomy.