When I moved into my new pad this past August, the landlord told me my next door neighbor had two 3 year-old girls and one teenage boy (15) - I met the woman who was renting it and she told me the same thing.
Within a week of me living here it became pretty apparent that there was also an infant, a 6 year-old boy and another 9 year-old boy also living there as well.
The real icing on the cake is that one of the two baby daddies that also live there - oh yeah, he's a registered hi-risk sex offender.
Your landlord is most likely just looking out for your neighbors and his property value.