how did this term came into existence?
It traces back to Ancient Greece and have been termed homophobia by scholars.
Homophobia
 tracing back to Ancient Greece 
put your hands up party in the usa It  is a song. who wrote it? Dr. Luke what is the song about? It has been described as "reggae-powered pop tune". can you please describe this genre that you just mentioned? It is a music genre that originated in Jamaica in the late 1960s. how did it get its name? The "Dictionary of Jamaican English" lists "reggae" as "a recently estab. sp. for "rege"", as in "rege-rege", a word that can mean either "rags, ragged clothing" or "a quarrel, a row". can you mention any of its features? It denotes the modern popular music of Jamaica and its diaspora. what percussion instruments are used in it? Bass can you name any other instrument that is used? Drums, guitars, keyboards and horns. what is the general theme of the lyrics? Love, socializing, religious themes, socio-political topics such as black nationalism, anti-racism etc have these faced any criticism? Yes, some dancehall and ragga artists have been criticised for homophobia, including threats of violence. what is this particular phobia about? It  encompasses a range of negative attitudes and feelings toward homosexuality or people who are identified or perceived as being lesbian, gay, bisexual or transgender (LGBT).
wiki:2452462
Homophobia [SEP] Origin of the term
Although sexual attitudes tracing back to Ancient Greece (8th to 6th centuries BC to the end of antiquity (ca. 600 AD) have been termed homophobia by scholars, and it is used to describe an intolerance towards homosexuality and homosexuals that grew during the Middle Ages, especially by adherents of Islam and Christianity, the term itself is relatively new. Coined by George Weinberg, a psychologist, in the 1960s, the term "homophobia" is a blend of (1) the word "homosexual", itself a mix of neo-classical morphemes, and (2) "phobia" from the Greek φόβος, phóbos, meaning "fear", "morbid fear" or "aversion". Weinberg is credited as the first person to have used the term in speech.