Genetic engineering is a difficult and very modern issue. Modern science has made possible the transfer of genes from one species to another. Debate about whether this should be allowed is becoming quite heated.
One of the most serious issues is transgenic organisms. These are developed by transferring genes for species to another. Recent examples are the mixing of the genes of a spider and a goat and the genes of a toad and potatoes.
Many people would not expect the Bible to provide a moral statement about transgenic modifications of species. However, it does, and in an unusual place. One of the puzzling passages of the Old Testament is Leviticus 19:19.
Do not mate different kinds of animals.
Do not plant your field with two kinds of crop.
Up until now, this verse has not made much sense. Animals of different species do not mate well, and they rarely produce offspring. One that has, the mule is infertile. If growing a crop, it does not make sense to plant two grains, eg. wheat and barley together. They will ripen at different times and will be difficult to harvest, unless one chokes the other out. This passage does not seem to apply to the sowing of pasture, as pasture is always a mixture of plants, even when growing naturally
This is all very hard to understand. The laws in Lev 19:19, are repeated in Deut 22:9,10, seem to prohibit activity that a sensible person would not generally want to do. There do not seem to be any reason for these laws.
Now in the modern world, in the context of genetic engineering and transgenic species, they suddenly seem to make sense. If two different animals are mated, their genetic material would be shared. The genes from one species would be transferred to another. Likewise, if two crops are grown together, they may cross-pollinate. Again the genes of one plant would be transferred to another. The laws are forbidding the transfer of genes from one species to another. God has set the world up in a way that prevents this from happening. In the natural situation species of plants or animals will not generally interbreed. When creating the plants and animals God complied with his own law.
The law was given to us, ready for the time when he would have the ability to transfer genes from one species to another. It forbids this activity. The reason is that in the beginning, God created each of the species after their own kind. When he finished he saw what he had done and it was good (Gen 1:31). He had created the species that are ideal for this world. If humans modify species they will no longer be good; man will be making the world worse. This is why creating new species is forbidden.
Transferring the genes of one species to another is morally wrong.