Due to the requirement of huge amount of starting material, it has been difficult for establishing a ChIP assay for small tissues to detect an association of a protein with transcription factors in vivo. I have recently developed a ChIP assay for transcription factors (Sry and Sox9) that utilizes chromatin from 20 intact embryonic testes (16-18 ts stage) without cross-linking protein to DNA. All ChIP assays published so far utilize cross-linking procedure to retain protein-DNA complex throughout the procedure. Question is “Is it possible to hold your protein-DNA complex for days without perturbing its binding?”.  I say yes. My experimental conditions retained that complex. Let’s see if this ChIP assay for transcription factors (Sry and Sox9) can be validated and standardized for several other transcription factors. At the end, there will be a way out for catching up mechanisms underlying early embryonic development.