Birthdays
December 21 Birthday: Personality, Birth Card and Numbers
People born on December 21 have the Ten of Hearts as their birth card: as a Ten of Hearts, they aim high and work hard, and can lose sight of the life the goal was meant to serve. Their Sun is in Sagittarius in the tropical zodiac and in Sagittarius in the sidereal zodiac, in Human Design Gate 10, Treading, and their birthday number is 21, which reduces to 3.
| Birth card | Ten of Hearts |
|---|---|
| Sun sign (tropical) | Sagittarius |
| Sun sign (sidereal) | Sagittarius |
| Human Design Sun gate | Gate 10, Treading |
| Gene Key | 10: Self-Obsession → Naturalness → Being |
| Birthday number | 21 (3) |
| Karma cards | Jack of Clubs and Five of Spades |
Find your birth card, free: Your birth card and planetary ruling card from your birth date.
Discover your Birth Card: One card out of fifty-two, decided by the day you were born. The shortest accurate description of you that exists.
The birth card for December 21 is the Ten of Hearts
Hearts is the suit of love, family and friendship, so your deepest lessons arrive through the people you care about, often the ones you cannot walk away from.
As a Ten, you aim high and work hard, and can lose sight of the life the goal was meant to serve. The card dares you to receive what you have built and make room for the people you built it for.
At work you do best with a large goal and the freedom to reach it your own way.
In love you need a partner who supports your goals, and they need to see you arrive for them as fully as for the work.
The Sun is in Sagittarius in both zodiacs
On December 21 the Sun is in Sagittarius whether you read the tropical zodiac, which follows the seasons, or the sidereal zodiac, which follows the constellations.
Sun in Sagittarius: You feel most alive when you are moving toward meaning: a vision, a truth, a horizon. The restlessness is not a flaw. The question is whether you are moving toward something or away from staying.
Around the change of sign, the exact day shifts by year. Your chart settles it.
The Sun is in Gate 10, Treading
In Human Design and Gene Keys, the Sun on December 21 is in Gate 10: your Personality Sun, and the key at the centre of your Life’s Work. Behavior and the conduct that creates integrity in living.
As Gene Key 10, it runs from the Shadow of Self-Obsession, through the Gift of Naturalness, to the Siddhi of Being.
Gates change every five or six days, so near the edges your Sun may sit in the gate next door. Your chart shows the line too.
Your birthday number is 21, which reduces to 3
The birthday number is a specific talent carried in the day you arrived: the day of the month, 21, read on its own and as 3.
3, The Voice: Expression. Three is not performance; it is creativity, play, and the word that needs to be said out loud.
You are here to say it, write it and make it. The work is finishing one thing rather than starting five, because expression only lands once it is complete.
Read together, these say more than any one alone
A birthday fixes your birth card, your Sun sign and your Sun gate. The year, the time and the place fill in the rest: the Life Path number, the rising sign and the whole Human Design chart. We read them together, each one a lens on you. That’s where a birthday starts sounding like a person.
Questions people ask
What is the birth card for December 21?
The Ten of Hearts.
What zodiac sign is December 21?
Sagittarius, in both the tropical and sidereal zodiacs.
What Human Design gate is the Sun in on December 21?
Gate 10, Treading. Near a gate change the exact day can shift by year.
What is the birthday number for someone born on the 21st?
21, which reduces to 3.