A vector and its use to generate genetically modified animals and cells is disclosed. One aspect involves a vector that comprises a sperm cell and one or more polynucleotide molecules bound to a sperm cell through one or more anti-sperm antibody linker. In one preferred embodiment, the one or more polynucleotide molecules encode for a gene product that confers desired characteristics in the cells or the animals. In another preferred embodiment, the genetically modified cells are able to produce desired therapeutic proteins. The association of the sperm, linker, and the one or more polynucleotide can occur in vitro or in vivo. In another embodiment, the genetically modified cells are transgenic chicken eggs in which one or more desired recombinant protein is expressed. In another aspect, genetically modified cells or animals are derived form the fertilization of an animal egg call with the vector described above. Another aspect includes cells, such as sperm cells or egg cells, and cell lines that are derived from these genetically modified animals or their descendants.