"Love child" is a synonym for "illegitimate child", meaning a child born out of wedlock. See Illegitimacy. In music:

"Love Child", a song by British jazz-pop duo Swing Out Sister from their 1992 album Get In Touch With Yourself

Love Child, a 1968 album by Diana Ross & the Supremes

"Love Child", a song by Deep Purple from their 1975 album Come Taste the Band

"Love Child", a number one hit from this album

Love Child, a 1982 film, based on a true story, starring Beau Bridges and Amy Madigan

Love Child, a 1990 album by Curved Air

"Love Child", a 1989 single by Canadian pop duo One to One

Love Child, a 1990 album by Sweet Sensation

Love Child, a 1986 novel by Andrew Neiderman

Love Child, a song by Accept from their 1984 album Balls to the Wall

Lovechild, a 2005 album by Nicole Wray