No one relies on organ donors or clones for spare parts. Advances in tissue engineering have made it possible to grow organs from stem cell cultures in vats or on biodegradable scaffolds, without the need to clone an entire human. Digits, skin, kidneys, livers, ears, noses, tongues, and genitals can be grown in under a month. Independently growing other organs and body parts (like hearts, lungs, eyes, and limbs) is more complex, and takes up to eight months.
Gengineered cells from livestock tissue are culutured in growth tanks and supplied with nutrients. This creates a continuously growing biomass of lean meat tissue, which is harvested whenever food is required or it gets too big for its vat. In many countries, fauxflesh has replaced 'natural' animal meat, which is often illegal. There is a small but lucrative meat-smuggling trade.
The most advanced form of tissue engineering is biogenesis, which speeds up the process by using nanomachines to rapidly assemble cells into tissue and organs. Biogenesis is more costly but about 4 times faster, taking weeks rather than months. It manufactures a wide variety of designer organisms, ranging from living toys like skullcats to human-like bioroids.
Bioroids are humanoid beings created using biogenesis. Most of the parts are biological, but some are not. For example, a polymer or carbon composite scaffolding is often left in place as the frame on which the skeleton was built. Deeper differences from the human norm will be apparent if their cells are examined. Baseline bioroids are designed to accept artificial chromosomes, with 'slots' into which genetic engineers can easily plug specific modules of genes. Much redundant 'junk DNA' material, such as transposons, is left out of bioroids. Bioroid tissues typically also contain clusters of nanofactories that produce special proteins that the designers couldn't take time to code into the genes, or which compensate for other shortcuts.
The basic bioroid design is similar to an upgrade human, but with major differences, typically including an upgraded immune system and reduced sleep cycle. All bioroids are sterile (though some female models can serve as surrogate mothers). Many have transgenic modifications that are similar to parahumans, but often more extreme, tailored for a particular occupation. This often extends to brain chemistry. For example, a military bioroid may always feel a rush of endorphins after vigorous exercise, a technical model may be able to go into a single-minded state that lets it focus on a problem, or a pleasure model may go into heat at the slightest provocation. In conjunction with proper training, these tend to result in bioroids who love their jobs.
A newly formed bioroid brain is designed to awaken in a state highly receptive to learning. Brain implants are integrated into the bioroid at this point, allowing it to undergo an intense educational regime that includes virtuality and slinky simulations and vocational training. The 'coach' is a personal infomorph hosted by the bioroid's brain implant, often a mind emulation of another bioroid of the same model who can be a big brother or sister to it. It uses a puppet implant to put the bioroid through physical exercises to build muscle memory, administers punishments or rewards (through non-damaging neural stimulation), and, most of all, encourages the bioroid to constantly strive to excel, solve problems, and reason creatively. This produces a trained, fully functioning 'adult' in 1 or 2 years. Depending on his viewpoint, he's a model citizen or a fairly clueless workaholic whose life experience and worldview are based on whatever slinkies the company fed him when he wasn't learning job skills.
Bioroids are controversial. People who see them forming in biogenesis tanks or examine diagrams of their skeletons, chromosomes, or nanofactories get a sense of 'living machine.' This impression can be reinforced by talking to any young bioroid, who is often similar in personality to every other bioroid of the same model. But a bioroid's brain and biochemistry are basically human; they have emotions, they reason, and they're subject to many of the same hormonal drives as people (although those nanofacs often have a say in it.) Bioroids who are 20-30 years old can be quite distinct individuals.