2 added 206 characters in body
source | link

The source is Pesochim 111aPesochim 111a and Horayos 13b,Horayos 13b where it says there that it isit's koshoh leshikchoh (harms one's memory). As far asRegarding relatives, Sefer Shemiras Haguf Vehanefesh page 333 brings from one sefer that it is mutar (allowed) (because the reason it is k.l.koshoh leshikchoh (harms one's memory) is thatbecause one diverts his attn.attention from Torah to ervahan Ervah, so(so it doesn't apply to these relatives). 

However, all the other seforim don't make this distinction, so it appears that they disagree.

The source is Pesochim 111a and Horayos 13b, it says there that it is koshoh leshikchoh. As far as relatives, Sefer Shemiras Haguf Vehanefesh page 333 brings from one sefer that it is mutar (because the reason it is k.l. is that one diverts his attn. from Torah to ervah, so it doesn't apply to these relatives). However, all the other seforim don't make this distinction, so it appears that they disagree.

The source is Pesochim 111a and Horayos 13b where it says that it's koshoh leshikchoh (harms one's memory). Regarding relatives, Sefer Shemiras Haguf Vehanefesh page 333 brings from one sefer that it is mutar (allowed) (because the reason it is koshoh leshikchoh (harms one's memory) is because one diverts his attention from Torah to an Ervah, (so it doesn't apply to relatives). 

However, all the other seforim don't make this distinction, so it appears that they disagree.

1
source | link

The source is Pesochim 111a and Horayos 13b, it says there that it is koshoh leshikchoh. As far as relatives, Sefer Shemiras Haguf Vehanefesh page 333 brings from one sefer that it is mutar (because the reason it is k.l. is that one diverts his attn. from Torah to ervah, so it doesn't apply to these relatives). However, all the other seforim don't make this distinction, so it appears that they disagree.