The kind of information that could lead to this graph is;<br />
  A has no sisters;<br />
  B, C, D, E, F, G, H &amp; I have just one sister each;<br />
  J, K, L, M, N, &amp; O have just $2$ sisters each;<br />
  P &amp; Q have just $3$ sisters each;<br />
  B, C, J &amp; K have no brothers;<br />
  D, E, F, P &amp; Q have just $1$ brother each;<br />
  A, L, M, N &amp; O have just $2$ brothers each;<br />
  G, H &amp; I have just $3$ brothers each.<br />