| ONLYONE | Lacking brothers and sisters, and just twelve months old |
| ROBLOWE | US actor whose TV credits include Brothers & Sisters and Parks And Recreation (3,4) |
| INFANCY | Period between one month old and twelve months old (7) |
| CHECHOV | Surname of the dramatist and short-story writer whose works include Uncle Vanya, The Three Sisters and The Cherry Orchard (7) |
| TINAFEY | Comedian who stars in Sisters and Whiskey Tango Foxtrot (4,3) |
| CHEKHOV | Anton -; Russian dramatist who wrote The Seagull, Three Sisters and The Cherry Orchard (7) |
| BRONTES | Creative sisters and little brother sent off (7) |
| YEARLING | Animal about twelve months old (8) |
| ONE | Any person twelve months old (3) |
| YEARLINGS | Yes, rook takes fishes between twelve and twenty four months old (9) |
| JUNO | Jupiter's wife and sister and the name given to iris subgenus Scorpiris (4) |
| FOOTSOLDIER | Member of the PBI, just twelve inches in service? (4-7) |
| JEWRY | Heard just twelve from biblical community (5) |
| TEG | Sheep between 12 and 24 months old (3) |
| HERA | The queen of the Olympian gods and sister and wife of Zeus in Greek mythology |
| HENRY | Name of eight kings of England, including the founder of Eton College, crowned at just eight months old (5) |
| RTE | One of just 12 in Alaska: Abbr. |
| FOOTWORK | With just 12 inches to operate, it gives shooters manoeuvrability (8) |
| URBAN | ___ VII, Pope for just 12 days in 1590 (5) |
| PUP | Dog that's only a few months old |
