Every cell in the body starts from the same genetic blueprint (the DNA in the fertilized egg), which contains the instructions for making all the different types of cells, including gametes (sperm or eggs) and all the specialized cells like skin, nerve, liver, immune, and brain cells.
The primary evolutionary purpose of all multicellular organisms (like humans) is to pass on genes to the next generation. So, in that broad sense, everything in the body ultimately serves the goal of making and protecting gametes — because without reproduction, the species wouldn’t survive.
However, somatic cells (the skin, nerve, liver, brain, immune cells, etc.) don’t function directly to produce gametes. Instead, they maintain the body’s health and functionality, which indirectly supports reproduction by keeping the organism alive and healthy enough to reproduce.
The DNA instructions in each cell include everything — the potential for any cell type — but which instructions get used depends on gene expression regulated by complex signals and environmental cues. This allows cells to specialize into skin, brain, or gametes, depending on their role.
The actual gamete-producing cells (in testes or ovaries) have special gene expression patterns and processes (like meiosis) that somatic cells don’t do.
So, the DNA is a complete “instruction manual” with everything needed for every cell type, including gametes, but the body’s many different cells play different roles. Gametes are crucial from an evolutionary and reproductive standpoint, but the other cells are crucial for survival, maintenance, and ultimately supporting those gametes.
We would be forgiven for thinking that we are here not to be persons but to be gamete factories.
Most take a more moderate view that the gametes are part of it.
Either way biology does not really respect personhood.
The Christians hold that the body dies but will one day rise again to eternal life. Jesus said there is no marriage in Heaven and that earthly marriage ends at death. He said the resurrected are like the angels - ie celibate. It is impossible to believe that God will raise a body that is so much about gametes and reproduction to live a celibate childless eternity. Jesus had no idea about genes so it is no wonder his doctrine slid off his tongue so easily.