Malta is the only country that accepts same sex married couples for Citizenship by investment (CBI). No other CBI program accept this sort of marriage. Caribbean countries do not accept same sex applications for CBI. Turkey also prohibit same sex marriage.
Gay marriage and LGBT in Malta has been legal since 1 September 2017, following the passage of legislation in the Parliament on 12 July 2017. A marriage or a civil union certificate is required as proof of marriage to be submitted with the citizenship application.
For example, in the Caribbean, St. Kitts and Nevis do not recognize same-sex marriages and are not allowed to apply for citizenship of St. Kitts and Nevis.