If you have ever designed anything in your life you will understand. What makes you think the body is not a design? You mean all the organs, blood vessels, neurons, skeletal structure and muscles just decided to join together one day on their own?
Sure, a human baby develops / grows from a egg cell / sperm. But there is a blueprint that made this possible.
When a building site is prepared for construction there is nothing there initially. Then the foundations are laid and the material shipped on site and gradually the building "grows" from out of nothing. But designers and workers still make it possible.
Your body is a design.
i know the body is not a design just because i have designed things. I would never put the retina at the back of the eye and invert it, most people have myopia. I wouldnt have our genitals be our sex organs, the cross contamination is stupid. I wouldn't have our mouth the sole opening for breathing and eating and talking, it demands that because of this stupid design (dolphins have a much better design) some people will choke to death eating, what fucking sense does that make. I could go on , but if we are designed then maybe there are a bunch of gods and this one happens to be the dumb one.