It's obviously a seedling...probably don't need a pic. If it's under 2 weeks old, you probably just need to do two things: Make sure your light is close enough (use your own judgement) factoring in that the closer to the light you are, the warmer it gets, so monitor your temps.
Secondly, get a gentle breeze blowing on it, the constant movement will quickly strengthen the little stalk. The little 4" desk fans work great for this.
If it's over two weeks old, getting some meat on it, and it's still tipping over...well then we need a pic.