(1) Whosoever performs an act of sexual intercourse with a consanguine descendant shall be liable to imprisonment not exceeding three years or a fine.

(2) Whosoever performs an act of sexual intercourse with a consanguine relative in an ascending line shall be liable to imprisonment not exceeding two years or a fine; this shall also apply if the relationship as a relative has ceased to exist. Consanguine siblings who perform an act of sexual intercourse with each other shall incur the same penalty.

(3) Descendants and siblings shall not be liable pursuant to this provision if they were not yet eighteen years of age at the time of the act.